KR20200067844A - Adaptive timing synchronization for the reception of bursty and continuous signals - Google Patents

Abstract

Examples of receivers, controller units (eg, for receivers) and related methods (eg, for receivers) are provided.
One receiver is provided which includes:
An adjustable sample provider 604, configured to provide samples of the input signal using adjustable sample timing;
A feedback path 630 configured to provide a feedback signal to the tunable sample provider 604 based on a timing error 634-the feedback path 630 is the tunable sample provider ( 604) includes a loop filter 636 that is configured to provide sample timing information 638; And
Replacement sample timing information that replaces the sample timing information 638 provided by the feedback path 630 when the input signal does not achieve a predetermined requirement for feedback-based sample timing adaptation ( replacement sample provider (640) configured to provide replacement sample timing information (642),
The replacement value provider 640 derives from the timing error information 634 over a longer period of time compared to the time period considered by the loop filter 636 for providing the sample timing information 638 It is configured to provide the replacement sample timing information 642 taking into account the quantity, or timing error information 634.

Description

Adaptive timing synchronization for the reception of bursty and continuous signals

The present invention relates to adaptive timing synchronization for the reception of bursty and continuous signals.

Transmission and signal reception scenarios

Faster and more flexible communication worldwide is a global trend. Terrestrial networks are suitable for densely populated areas. However, this trend will include sea, sky, diverse and sparsely populated areas, as well as satellite communication scenarios that may be included in its requirements. A new beam-hopping concept was introduced to optimally adapt the technology to the changing traffic needs over time and location. Unlike quasi-static illumination in a conventional multi-beam satellite system, the satellite turns on and off the satellite's beams according to a specific schedule derived from user terminal location and traffic needs. Advantages in terms of system capacity optimization and better matching of traffic needs are shown in [1] and [2].

The upcoming Eutelsat Quantum-Class Satellite is software-defined that provides in-orbit flexibility in all operational parameters of the payload, including service area definition, frequency planning and power allocation. It is a Ku-band satellite [3]. It also supports a beam hopping function that will provide a visible presence beyond Earth, as seen by satellites with great flexibility in capacity allocation. It is considered the first open standard beam hopping system and will support independent beam hopping networks [4]. The system, scheduled for service in 2019, utilizes fast and smooth beamforming reconstruction that can be applied to a variety of applications such as mobility, disperse geographical areas, and emergency and information services.

For example, a suitable wave waveform plays an important role in implementing such a system. Suitable is the recently released super-framing specification of the DVB-S2 standard. An example of a corresponding application is shown in FIG. 1, and the satellite 102 (transmitter) has three service areas 104, 106, and 108 according to a beam-switching time plan (BSTP) 121. (E.g., geographically distinct terrestrial areas).

The concept of BSTP can be understood as a generalization of scheduling plans. Time is subdivided into periodic time slots of individual duration per each specific coverage area, each time slot in turn subdivided into a plurality of super-frames. Each time slot may be an illuminated time slot (or period) or a non-illuminated time slot. Each receiver in the coverage area means receiving a beam signal from the transmitter during the illuminated time slot. Each receiver in the coverage area does not generally mean receiving a beam from a transmitter during a non-illuminated time slot. The definition of BSTP is generally performed to optimize transmission from the transmitter to the receivers to meet data traffic needs that vary with time and location.

The definition of certain BSTPs 121 may be due to different amounts of remote terminals (receivers) 110, 112, 108 per service area 104, 106, 108 and different traffic needs. As a result, different numbers of super-frames are transmitted to different service areas (eg, based on switching activity performed by satellite 102). Because the requests vary with time and location, the scheduler at the gateway 116 calculates new BSTPs 121 and satellites the obtained switching schedule (eg BTSPs) 102 ) (Or other device to be a transmitter) (for example, by sending a signal). As can be seen from [6], so-called super framing formats 2, 3 and 4 can be used in the beam hopping system. (In some examples, the gateway may be integrated into the transmitter.)

In FIG. 1, which shows system 100, satellite 102 (eg, receiving communication from gateway 116 and/or following selected BTSPs) has coverage area during time slots 120 ′. Beam 104 towards the remote terminal 110 at 104, beam 122 towards the remote terminals 112 at the coverage area 106 during slot 122', and time slot 124' While directing beam 124 from coverage area 108 towards remote terminal 114. The time slots for receiving the beam from the transmitter for each remote terminal are illuminated time slots. For terminals 110, time slots 122` and 124` are non-illuminated time slots for terminals 110, while time slots 120` are illuminated time slots. In some examples, the time slots 120', 122', 124' do not overlap each other and realize time multiplex. Therefore, it is generally preferable that the terminals 110 can reliably distinguish the illuminated time slot 120' from the non-illuminated time slots 122' and 124'.

A satellite, such as satellite 102, can support several beam hopping networks, that is, some systems, such as system 100.

It should be noted that the transmission example in FIG. 1 represents only one possible example of a number of possible system configurations. An important feature of the concept is the ability to reconfigure almost randomly to best meet the traffic needs. Fortunately, the particle size of the lighting duration can be counted as a multiple of the super-frames duration. The satellite operates based on time slots and is freely configurable and can have a supported particle size of 1 μs, for example, to provide support for various symbol rates. However, the waveform used for data transmission provides a granularity based on the described baseline super-frame duration or super-frame duration. The terminal uses the waveform features. It should be noted that other framing concepts and conventions other than the super framing may also be applied. For example, a cascaded super-frame duration can be specified, where there is a short baseline super-frame duration and another super-frame duration is a multiple of this baseline super-frame duration.

From a remote terminal (110, 112, 114) perspective, four reception scenarios can occur in a beam hopping satellite system with respect to one carrier frequency:

• Repetitive illumination receiving a signal of one beam (for one service area or coverage) corresponding to the case shown in FIG. 1. As shown in Fig. 1, the start 120a (or 122a, 124a) and end 120b (or 122b, 124b) of the lights correspond to the start and end of reception. The receiver 110, for example, does not receive the beam 122 or 124 towards another area. In particular, there may be a problem with the timing of the receiver when the receiver is not illuminated.

• Repetitive illumination (for different service areas or coverage) to receive signals from multiple beams. For smooth handover of terminals, adjacent coverages can be slightly overlapped. Consequently, a single shot at the edge of the coverage can receive illumination of at least two beams, as shown in FIG. 2A. For example, beam C (exactly intended to be received by a particular receiver during illuminated slots 220 formed by super frames SF7 and SF8) is received at maximum power P2. However, the beam D (actually intended to be received by different neighboring service areas during slots 222 formed by super frames SF9 and SF10) is also received at a power level P1 less than P2. Note that at the end 220b of illumination by beam C, which also corresponds to the beginning of illumination 222a by beam D, only a slight decrease in power P2-P1 occurs. This phenomenon can lead to unwanted effects. The receiver may want to avoid receiving unnecessary transmissions. For example, power consumption can be reduced by avoiding the decoding of unwanted transmissions. On the other hand, reception may be desirable, for example, to improve terminal synchronization using unintended transmissions that may have a high signal-to-noise ratio (SNR). However, note that using the unintended transmissions also requires more complex synchronization procedures to cope with this challenge. If the terminal synchronization procedures do not recognize this scenario, they may be confused and terminal synchronization will fail.

ㆍContinuous lighting with one signal is another extreme. All users are in one service area (coverage area), for example a fleet of ships, and only beam forming is used to align the beam steering. Therefore, the optimal configuration is to permanently illuminate the service area.

ㆍNo lighting. This occurs when all terminals are off and there is no request. However, once, the first terminal in the service area is turned on. And, for example, by sending a request signal to the transmitter (eg, satellite 102), a secondary system control channel may be used by the terminal to request illumination. Thereafter, gateway 116 (eg, known by satellite 102) will define super-frames suitable for communication with the first terminal and will issue a BSTP update that includes the new coverage area. The first terminal will then operate according to one of the above scenarios.

The length of each light can be changed according to the BSTP update and the duty cycle of the light.

Problems and challenges

From the perspective of terminals 110-114, the main problem is to achieve accurate timing (re-) synchronization to be robust enough to handle all the scenarios described above. The initial coarse acquisition is also very straight forward. At the end of the lighting (eg, 120b, 122b, 124b, 220b), all synchronization algorithms may converge and offset may be compensated. However, the challenge lies in re-synchronizing immediately when lighting is restarted (e.g., at 120a, 122a, 124a) to continue demodulating payload data after a potentially existing preamble sequence. The required accuracy is in the order of the parts of the symbol duration, ie timing or sampling phase. Sampling phase offset creates self-interference that can cause data demodulation errors.

Looking at the immediate resynchronization, another problem is identified. During timing resynchronization at the start of illumination, the preamble sequence detection marks the start of the burst and (re-)initializes the data framing tracker. This tracker marks different data fields and payload data frames according to a burst structure. Since timing resynchronization and preamble sequence detection can be performed in parallel, there is very little symbol uncertainty with respect to the framing grid (expected from previous bursts by signaling or history and/or common burst structures). . Steady-state symbol grid with +/- 1 or +/- 2 symbols away from the symbol-precise data framing grid where timing re-synchronization is expected due to disturbances such as noise. There is a possibility/probability to converge to. This may occur because the convergence time may be longer than or equal to the detection of the start preamble sequence of the burst and the duration of the start preamble sequence of the burst. If not compensated, this symbol offset results in data demodulation and decoding errors.

A further problem is to have a suitable and dependable detection strategy to determine the start and end of the lighting. The latter information must be reliably estimated and signaled to other functions and/or equipment, such as managing timing synchronization. If the start of illumination is incorrectly determined too early, only noise samples instead of data are processed and synchronization is disturbed. If the lighting start is determined late, time is wasted because valuable synchronization data is lost and not used for resynchronization. Again, it results in data demodulation errors and data loss.

Another aspect is the need for wideband communication, ie high-speed data transmission. This comes from the ime-multiplex approach of the data transmission. If the existing system permanently serves each of the 10 service areas at a symbol rate of, for example, 30 MHz, the beam hopping system uses a 300 MHz broadband carrier shared in 10 lighting time slots to achieve the same throughput. in need. As a result, the terminal must support significant processing power to cope with high data throughput during lighting.

Prior art solutions and their disadvantages

There are two existing concepts that address the major issues mentioned above. However, both show some drawbacks overcome by the examples according to aspects of the invention.

1. Detection and buffer:

This concept is first applied to the detection stage where the start and end of the lighting are detected. Non-data-aided (NDA) power detection-based algorithms do this and/or use data-aided (DA) known-sequence detection (eg, by correlation). Can be used. Data samples received based on this detection and determination are stored in a buffer. Coarse and fine synchronization (with respect to timing and frequency) and all further processing is performed based on buffered data. Thanks to this storage, the synchronization process can work repetitively/recursively on the buffered data to improve offset compensation.

2. Freezing the timing loop during periods two trillion people (Freezing timing loop during absent illumination) :

The timing loop concept shown in signal processing 300 of FIG. 3 is a standard approach for synchronizing sampling offsets in a recursive manner. Modules "timing interpolator" 304, "automated gain control (AGC)" 312, "timing error detector (TED)" 332 and "loop filter" Different configurations and processing rules for 336 can be found in standard literature such as [7] and [8]. A matched filter 308 is also used.

The timing interpolator 332 performs resampling of the input data 302 according to the control signal of the feedback path 330 from the loop filter 336. Using the loop filter 336, the adaptive rate and dynamic characteristics of the entire loop can be affected. This filter 336 generally has low pass and averaging characteristics to smooth the instantaneous timing error/offset calculated at TED 332. This principle is suitable for continuous signal reception (works fine). After the initial convergence of this control loop, it is accurate re-sampling to compensate for timing offset (sampling phase and sampling frequency) by permanent re-adjustment through the feedback path 330. Gives

The freezing controller 350 keeps the adaptation processes constant once the freezing is turned on. This may be necessary if there is no light or too weak light.

Concept 1 seems to be a practical solution to this problem. However, very large buffers may potentially be needed to handle long lights. You may also experience throughput limitations with regard to worst-case system configurations, such as supporting various scenarios and receiving continuous signals. Therefore, this method is more suitable for low to medium symbol rates and rather low duty cycles. This low duty cycle can be either a sufficiently long illumination absence duration combined with one or several super-frames per light, or a complete super-frame with only the own data frame received and other user data ( complete super-frame) represents any one of the existing burst mode reception scenarios to prevent reception.

Concept 2 can in principle be applied under conditions in which the freezing controller operates correctly in order not to compromise the offset compensation already achieved. However, in-depth investigation showed that the control signal of the feedback path of the timing loop showed too much jitter. This is a problem because the last value freezes and remains constant while there is no lighting. Therefore, the loop cannot be updated, so the actual error of the value accumulates. As a result, re-synchronization at the start of the lighting starts off by an arbitrary amount of symbols from the expected grid, so that the preamble/known sequence is located at an unexpected time with respect to the estimated sampling.

Power detection methods seem easy. And the term detection does not explicitly indicate what has been detected. Intuitively, we will aim to detect the rising and falling edges of the (potentially averaged) received power. The two classic approaches are analyzed as follows:

ㆍThreshold-based power detector:

The minimum and maximum power is determined over the observation time from the average received power signal. Thresholds are calculated at this minimum/maximum power value for rising edge detection and falling edge detection. This procedure can be repeated to track the power of a slight change received over time.

ㆍTilt-based power detector:

The slope is calculated from the differential signal, that is, the received power signal averaged by means of subtracting the power value of the time distance Δ. When the power is greatly changed, a peak is generated in the differential signal, and it can be confirmed against a threshold.

The following two types of simulation results are provided for a single light at SNR = -3dB (assuming the worst SNR is expected). 4 and 5, a threshold-based detector and a slope-based detector are considered respectively. In both cases, since the fluctuation of the instantaneous power value is too high, the instantaneous power value is averaged first. Here, averaging is implemented by infinite impulse response (IRR) filters, where two configurations regarding the depth of averaging, IIR1 and IIR2, are compared. 4 and 5 show the detection of power high/low. However, other methods, such as linear averaging, are also possible in principle.

In FIG. 4, the maximum and minimum average power values are determined from IIR2 because they are more precise due to strong averaging (“PW maximum (IIR2)”, “PW minimum (IIR2)”). From this, the threshold values are calculated as "threshold (IIR1)" and "threshold (IIR2)". This detection was successful in all of the evaluated IIR configurations because it considered the scenario of only receiving a single beam. However, testing in different scenarios, as shown in FIG. 2A, indicates that different beam signals cannot be properly distinguished, which results in missing rise or fall detections. As a result, enormous efforts will be required for case handling and error detection.

In FIG. 5, the differential signal is calculated based on IIR1 using Δ = 2048 samples. Variations around zero are shown. The peaks 502 and 504 in the differential signal can be observed and detected at least theoretically, but there is a possibility that detection is unsuccessful (eg, under low SNR). This is due to the noise enhancing nature of differential signal computation. This unreliable detection performance becomes even more serious in multiple beam scenarios as shown in FIG. 2A. When transitioning from 220 to 222 (220b), the size of the peak 504 will be reduced by a very small amount, resulting in an undesirable possibility that the peak 504 will be confused with noise.

For the unexpected symbol offset problem after timing resynchronization convergence, the two traditional approaches are performed differently. Concept 1 will not exhibit this problem at all, as iterative/recursive improvements in synchronization automatically compensate. This is because synchronization quality is measured after each improvement iteration that results in the detection of symbol offset. Concept 2 of a simple implementation will provide only framing grid detection by means of detection of a preamble sequence. Therefore, there is no counter-measures to properly deal with the unexpected symbol offset problem in Concept 2.

In conclusion, the simple or existing approach does not adequately solve the problem.

Citation of prior art literature

US 2002/0186802 A1 discloses a method for adaptively adjusting the parameters of a timing loop. The loop filter gets a phase error at the phase detector. The loop filter includes a first gain or scaling step (with initial gain α) and a second gain step (with initial gain β). The timing loop parameters α and β can be corrected based on the difference between the average frequency error and the current frequency error being below or exceeding a predetermined threshold.

US 2014/0312943 A1 discloses a phase locked loop (PLL).

US 2015/0002198 A1 discloses a PLL capable of operating in normal mode or speed mode. The speed mode is activated, for example, when the magnitude of the difference between the current phase error value and the value stored in memory is less than a threshold.

However, the prior art does not solve the problem discussed above. For example, the prior art does not allow to correctly distinguish between a lighting scenario and a wrong lighting scenario. In addition, the prior art cannot avoid freezing of timing values during non-illumination periods.

Summary of the invention

According to aspects, an adjustable sample provider configured to provide samples of an input signal using adjustable sample timing;

A feedback path configured to provide a feedback signal to the adjustable sample provider based on a timing error, wherein the feedback path includes a loop filter configured to provide sample timing information to the adjustable sample provider Ham -; And

Replace sample timing information that replaces the sample timing information provided by the feedback path when the input signal does not meet the predetermined requirements for feedback-based sample timing adaptation. Includes a replacement value provider configured to provide,

The replacement value provider is a quantity derived from the timing error information, or timing error information (timing) over a longer time period when compared to a time period considered by the loop filter for providing the sample timing information. A receiver is provided, configured to provide the replacement sample timing information taking into account error information.

According to aspects, an adjustable sample provider configured to provide samples of an input signal using adjustable sample timing;

A feedback path configured to provide a feedback signal to the adjustable sample provider based on a timing error, wherein the feedback path includes a loop filter configured to provide sample timing information to the adjustable sample provider Ham -; And

Provides replacement sample timing information that replaces the sample timing information provided by the feedback path when the input signal does not meet the predetermined requirements for feedback-based sample timing adaptation. It includes a replacement value provider configured to (replacement value provider),

The replacement value provider is configured to temporarily smooth sample timing information provided by the loop filter and/or loop filter-internal timing information to obtain the replacement sample timing information, A receiver is provided.

The replacement value provider is a quantity and/or timing error information derived from the timing error information over a period of time longer than a period of time for timing error information considered by the loop filter to provide current sample timing information. And/or averaging sample timing information provided by the loop filter.

The replacement value provider can be configured to average or filter over a longer period of time when compared to a loop filter to provide the replacement sample timing information.

The loop filter is a low pass filter and can be configured to perform averaging or equally weighted averaging that gives less weight to past input values when compared to current input values.

The replacement value provider performs linear averaging by means of equal or different weights for the input values of the timing error information and/or the timing error information and/or sample timing information provided by the loop filter. It can be configured to perform.

The replacement value provider can be configured to select samples of the sample timing information to perform filtering or averaging on selected samples.

The replacement value provider may be configured to perform a filtering or averaging on the selected samples in an amount derived from the timing error information, or to adaptively select samples of the timing error information. Configured to perform the analysis,

The receiver is configured to increase the number of selected samples for signals with relatively high noise and/or decrease the distance between the selected samples when compared to signals with relatively low noise.

The replacement value provider adaptively samples samples to perform filtering or averaging on the selected samples to increase the average gain over average length or filter length. It can be configured to choose.

The replacement value provider can be configured to use the down sampled version to perform filtering or averaging on the down sample version.

The replacement value provider can be configured to use an amount derived from the timing error information or a down-sampled version of the timing error information to perform filtering or averaging on the downsample version,

The sampling rate of the down-sampled version is a first sampling rate that is an amount derived from the timing error information or between 100 and 10000 times or between 500 and 2000 times slower than the sampling rate of the timing error information. to be.

The replacement value provider may be configured to selectively consider a quantity derived from the timing error information for providing the replacement timing information, or samples of the timing error information,

The current replacement timing information is obtained based on samples of time periods of at least two different considered input signals while the input signal satisfies a predetermined condition.

The replacement value provider is a quantity derived from the timing error information or a sample of the timing error information, based on a lookup table and/or configuration data according to a communication scenario or configuration. It can be configured to select them.

The replacement value provider is an amount derived from the timing error information or an amount derived from the timing error information for the derivation of the replacement sample timing information based on the analysis of the timing error information, or the timing error information It can be configured to adaptively select the samples of the.

The receiver can be configured to increase the loop filter characteristics and/or the loop gain for an initial transitory interval.

The receiver is configured to re-configure the loop gain/loop filter characteristics while operating based on modified reception conditions.

The receiver increases the loop filter characteristics and/or the loop gain of the loop filter for a signal with a relatively high SNR in relation to a signal having a relatively low signal to noise ratio (SNR). And/or to reduce the loop filter characteristics and/or the loop gain of the loop filter for signals with a relatively low SNR relative to the signal with a relatively high SNR.

The receiver provides a feedback mode in which the feedback signal from the feedback path is provided to the adjustable sample provider and a replacement value provision mode in which the replacement sample timing information is provided to the adjustable sample provider. ) Can be configured to switch.

The receiver is configured to switch to intermediate mode in which intermediate values are provided to the adjustable sample provider-the intermediate values are values between the values of the feedback signal and the replacement sample timing information. Obtained -,

The transition from the feedback mode to the intermediate mode and from the intermediate mode to the replacement value providing mode, and/or

The transition is a transition from the replacement value providing mode to the intermediate mode and from the intermediate mode to the feedback mode.

The receiver may be configured to provide intermediate replacement sample timing information to smooth transition from the feedback mode to the replacement value providing mode, or vice versa, in the intermediate mode.

The receiver can be configured to provide reconstruction information and/or data from the replacement value provider 640 to the loop filter.

According to aspects, a controller unit for recognizing a transmission to be received is provided,

The controller unit performs determining whether the power of the received signal or the quantity from the power lies in a limited interval, and

Based on the determination, it can be configured to recognize the transmission to be received.

The controller unit may be configured to identify whether the received signal includes a previously determined power level.

The controller unit is configured to recognize the length of at least one limited time period during which the received signal includes a power level, an amount derived from the received signal, or how long the power of the received signal is within the limited interval. It can be configured to determine whether it lies.

The controller unit may be configured to check whether the recognized length of the limited time period while the received signal includes the power level satisfies a predetermined condition, in order to support recognition of a transmission to be received. .

The controller unit may be configured to recognize different power levels of the received signal or the amount derived from the power.

The controller unit can be configured to track the duration at which the different power levels appear to derive power level scheduling information.

The controller unit may be configured to check whether the current power level lies in a limited interval and interval boundaries determined based on the previously derived power level scheduling information.

The controller unit is configured to selectively switch components of the processing or the receiver or the processing or receiver to a reduced-power-consumption mode based on the derived power level scheduling information. Can be configured.

The controller unit may re-configure the receiver differently for different time periods and/or receive the data to rank the different time periods to recognize the time periods for the transmission to be received. It can be configured to recognize periods of time during which the different power levels and the different power levels of the signal, or the amount derived from the power, appear.

The controller unit is configured to recognize different power levels of the received signal, or of the amount derived from the power, in order to select a time period with a relatively high power level in relation to a time period with a relatively low power level. Can be configured.

The controller unit can be configured to store time information depicting characteristics of time portions of different levels of the received signal and to store information about the power levels of the received signal or the amount derived from the power. ,

At the next moments, it is configured to recognize time periods associated with the transmission to be received, at least based on the stored time information.

The controller unit may include a special activation mode “exploit other illumination” based on the qualification of the other illumination(s) and the detection of different illumination power levels.

The controller unit can be configured to determine the start and/or end of a period of transmission to be received based on the power level.

The controller unit may be configured to decode and/or detect at least one piece of information encoded in the received signal to determine the start and/or the end of the period of transmission to be received.

The controller unit detects a slope of the power above or below a predetermined threshold,

Using the time information obtained with previous power level determinations,

Decoding specific information encoded in the received signal, and/or

Detecting quality information or deducing it from other modules,

Using data and/or commands signaled from a transmitter

It may be configured to recognize the start and / or the end of the period of the transmission to be received by a redundant (redundant) or supporting (supporting) technology comprising at least one of.

The controller unit is configured to recognize and/or dynamically define at least one power level based on the determination that at least two consecutive power samples are placed within limited intervals associated with a specific power level. Can be.

The controller unit

As a first condition, it is determined whether a current sample of a positive amount derived from the power, or power of the received signal, lies within an interval determined by the positive, derived from the power, or a first preceding sample of the received signal power. And

As a second condition, an interval determined by the positive, derived from the power, or the current sample of the power of the received signal is also the positive, derived from the power, or a second preceding sample of the power of the received signal Can be configured to determine if it lies within,

The controller unit may be configured to recognize a continuity of power levels when both the first condition and the second condition are satisfied.

The controller unit is a sequence of the positive number derived from the power that does not satisfy the first condition and/or the second condition without recognizing the end of the power level, or a predetermined number of the power of the received signal. It can be configured to tolerate (tolerate) the sample,

Configured to recognize the end of the power level if the positive, or successive samples of the power of the received signal derived from a greater number of the power than a predetermined one do not satisfy the first condition or the second condition Can be.

The controller unit is greater than an interval determined by the positive, derived from the power, or the current sample of the power of the received signal, from the positive, derived from the power, or the immediately preceding sample of the received signal. It can also be configured to determine whether it lies outside of a tolerance interval,

The controller unit may be configured to recognize the end of a power level when the current sample of the power of the positive or the received signal derived from the power is first placed outside the allowable interval.

The controller unit may be further configured to operate along at least the first and second operating modes, and the amount of power derived from the power in at least one of the first and second operating modes, or the power of the received signal is limited. Technology to determine if it lies within the gap,

Technology to determine if power is determined at the expected time period,

A technology for decoding or detecting specific information encoded in the signal to be received,

Technology to check quality information,

Technology to check the satisfaction of the criteria according to the information signaled from the transmitter,

It may be configured to perform at least one of techniques for detecting whether the slope in the power is above or below a predetermined threshold,

The controller unit is configured to use at least one different technique in the first mode of operation in relation to the second mode of operation.

The controller unit may include a first mode for determining whether the amount derived from the power or the power of the received signal lies within a limited interval, without considering information encoded in the signal; And

Determine whether the amount derived from the power, or the power of the received signal lies within a limited interval, and

Verifying the correctness of the determination based on whether the encoded information in the received signal conforms to the recognition of the transmission to be received based on the power

2nd mode

It can be configured to operate along at least two of the operation modes.

The controller unit may be configured to derive or obtain an amount derived from the power from an automatic gain control (AGC), and/or a matched filter (608).

The controller unit, wherein the amount associated with the power is an infinite impulse response (IRR) filtered version of the power information.

The controller unit includes power for determining at least one power level to be used later to recognize a transmission to be received;

Time information;

Quality information

It may be configured to perform an initialization process for obtaining parameters related to at least one or a combination thereof,

The controller unit receives the signaled information to perform the initialization, or the amount of time or the amount of power derived from the power over the period of the received signal to perform the initialization It can be configured to analyze the evolution (temporal evolution).

The controller unit may be configured to adaptively modify an upper interval boundary value and a lower interval boundary value for the power based on historical values of the power. .

The controller unit can be configured to control the receiver.

The controller unit includes a first state in which the feedback path provides the feedback path to the adjustable sample provider; And

A second state in which the replacement value provider provides the replacement sample timing information to the adjustable sample provider

It can be configured to control at least one of the above or below the receiver to choose from.

The controller unit can be configured to control at least one of the above or below receivers to determine the predetermined requirement to be satisfied by the input signal.

The controller unit providing the feedback signal 638 to the adjustable sample provider 604 when the feedback path 630 recognizes that the controller unit 650, 654 is to receive the transmission; And/or

The replacement sample timing information 642 is adjusted by the adjustable sample provider 604 when the replacement value provider 640 recognizes that the controller unit 650, 654 is not a transmission to be received or there is no transmission. )

It can be configured to control at least one of the above or below the receiver to select.

The receiver may further include any of the controller units described above and/or below.

According to aspects, the system can include a transmitter and a receiver, the receiver being any of the above or below receivers, and the transmitter is configured to transmit a signal to the receiver.

According to aspects, the transmitter has a system that can be a satellite.

The transmitter can be configured to perform transmission according to a beam-switching time plan (BSTP) and/or according to a scheduling transmission,

The BSTP and/or the scheduling can be defined such that the signal is intended to be transmitted to the receiver for at least one first interval, and the signal is not intended to be transmitted to the receiver for at least one second interval. System.

The system may include a plurality of receivers, and the transmitter may be configured such that a specific beam is directed toward the intended receiver in accordance with BSTP and/or scheduling so that the signal power is temporarily improved in the direction of the intended receiver. Can be.

The receiver may use the feedback signal 638 in determining that the transmitter is directed to the receiver, and/or non-determination of transmission from and/or in a determination that the transmitter is not intended for the receiver. In may be configured to use the replacement sample timing information 642.

The transmitter can be configured to operate according to a continuous signal condition in which at least one beam is continuously directed to one receiver, and a bursty signal condition in which different beams are directed to different receivers.

A method for receiving an input signal includes processing samples of the input signal using adjustable sample timing;

Fitting the sample timing based on a feedback signal based on a timing error, the feedback signal being obtained using a loop filter providing sample timing information; And

And providing replacement sample timing information to replace the sample timing information provided with the feedback signal when the input signal does not satisfy a predetermined requirement for feedback-based sample timing adaptation,

The replacement sample timing information is obtained by taking into account the amount derived from the timing error information, or timing error information, over a longer time period when compared to the time period considered by the loop filter to provide the sample timing information. Lose.

A method for receiving an input signal includes processing samples of the input signal using adjustable sample timing;

Fitting the sample timing based on a feedback signal based on a timing error, the feedback signal being obtained using a loop filter providing sample timing information; And

And providing replacement sample timing information to replace the sample timing information provided with the feedback signal when the input signal does not satisfy a predetermined requirement for feedback-based sample timing adaptation,

The replacement sample timing information is obtained by temporarily smoothing the sample timing information provided by the loop filter to obtain the replacement sample timing information.

Determining an amount derived from the power 656, or whether the power of the received signal lies within a limited interval, and

Recognizing the transmission to be received based on the determination

A method for recognizing a transmission to be received, which may include.

The method may include the above and/or the following methods,

The provision of the replacement sample timing information in the above and/or the following method and the provision of the feedback signal can be controlled by the above and/or the following methods.

A computer program capable of performing at least one of the above and/or below methods when executed by a processor.

According to aspects, find a first frame candidate at a predicted position and at least one second frame candidate shifted from the first frame candidate for a predetermined offset,

Evaluating characteristics of the at least one second frame candidate and the first frame candidate,

The correct frame is identified based on the evaluation.

A receiver is provided, comprising a data processor configured to.

The receiver is configured to identify the correct frame based on cross correlation processes.

Each frame candidate and

Known sequence of symbols

It can be configured to perform cross-correlation processes.

The receiver identifies the correct frame based on the cross-correlation processes,

Demodulate and/or decode the frame headers of the first and second frame candidates,

Re-modulate and/or re-encode the sequence of symbols, and

Perform the cross-correlation processes between each frame candidate frame header and the re-modulated and/or re-encoded version of the frame candidate frame header

It can be configured to.

The receiver starts/ends and/or frame symbols of frame signaling 806 to compensate for the detected temporal offset between the frame signaling 806 and the frame symbols 804. It can be configured to perform a correction procedure (correction procedure) for (804).

The receiver can be configured to perform an evaluation operation on the results of the correlation processes to verify the correct frame.

The receiver is associated with a first threshold 902 and each frame candidate to verify the correct frame if the correct frame is the only frame candidate associated with a correlation value greater than the first predetermined threshold. It can be configured to compare the cross-correlation results of.

The receiver at least a predetermined number of frame candidates associated with each of the frame candidates associated with each frame candidate to suppress verifying the correct frame when associated with the smaller predetermined threshold and cross correlation values within the larger predetermined threshold. Can be configured to compare the correlation results to a larger threshold and a smaller predetermined threshold,

Error in the attestation that the predetermined number of frame candidates is associated with cross correlation values greater than the predetermined threshold and at least a predetermined number of frame candidates is associated with cross correlation values smaller than the smaller predetermined threshold. It can be configured to inform.

The receiver selects if at least a predetermined number of frame candidates are associated with cross correlation values greater than the predetermined threshold and at least a predetermined number of frame candidates is associated with cross correlation values smaller than the smaller predetermined threshold. Can be configured to compare each of the cross-correlation results associated with each frame candidate to a larger predetermined threshold and a smaller predetermined threshold to suppress verifying the frame, and

Error in the attestation that the predetermined number of frame candidates is associated with cross correlation values greater than the predetermined threshold and at least a predetermined number of frame candidates is associated with cross correlation values smaller than the smaller predetermined threshold. It can be configured to inform.

According to aspects, an adjustable sample provider (eg, timing interpolator) configured to provide samples of an input signal using adjustable sample timing (eg, by the sample timing information);

A feedback path configured to provide a feedback signal to the tunable sample provider [eg, timing interpolator] based on a timing error (eg, as determined by a timing error detector) [ For example, TED, loop filter]-the feedback path includes a loop filter configured to provide sample timing information to the tunable sample provider [the loop filter is for example timing provided by the timing error detector] Filter or average error values] -;

Pre-determined requirements for input signal feedback-based sample timing adaptation [eg, based on a specific sequence encoded in the input signal and/or power level and/or associated with the input signal] Or based on power, based on the control exerted by the controller and/or when the requirement associated with the absence of lighting is not achieved], replacement sample timing information to replace the sample timing information provided by the feedback path ( a replacement value provider configured to provide replacement sample timing information,

The replacement value provider is a quantity derived from the timing error information, or timing error information (timing) over a longer time period when compared to a time period considered by the loop filter for providing the sample timing information. A receiver is provided, configured to provide the replacement sample timing information taking into account error information.

According to examples, an adjustable sample provider (eg, timing interpolator) configured to provide samples of the input signal using adjustable sample timing (eg, by the sample timing information);

A feedback path configured to provide a feedback signal to the adjustable sample provider [eg, timing interpolator] based on a timing error (eg, as determined by a timing error detector (TED)) path) [eg, TED, loop filter]-the feedback path includes a loop filter configured to provide sample timing information to the tunable sample provider [the loop filter is, for example, to the timing error detector Filtering or averaging the timing error values provided by -;

Pre-determined requirements for input signal feedback-based sample timing adaptation [eg, based on a specific sequence encoded in the input signal and/or power level and/or associated with the input signal] Or based on power, based on the control exerted by the controller and/or when the requirement associated with the absence of lighting is not achieved], replacement sample timing information to replace the sample timing information provided by the feedback path ( a replacement value provider configured to provide replacement sample timing information,

The replacement value provider may temporally smoothen the sample timing information provided by the loop filter and/or loop filter-internal timing information to obtain the replacement sample timing information [eg For example, a low-pass-filter order time average is constructed.

The replacement value provider is configured to provide current sample timing information (time period considered by the loop filter for providing the sample timing information) [eg, filter length of the FIR filter used as the loop filter]. Averaging amount and/or timing error information derived from the timing error information and/or sample timing information provided by the loop filter over a period of time longer than the period of time for the timing error information considered by the loop filter It can be configured to.

The replacement value provider is configured to provide the replacement sample timing information. [For example, the impulse response of the replacement value provider for the value of the timing error information is longer than the impulse response of the loop filter for the value of the timing error information. ; Alternatively, the replacement value provider considers the values of the timing error information over a first period of time to provide current replacement sample time information, while the loop filter is compared to a first period of time to provide current sample time information. In that the values of the timing error information are considered over a second period of a short period of time] [the loop filter may be, for example, a low-pass filter, and consequently the same for the past input value when compared with the current input value. Weighted averaging or relatively small weighted averaging may be performed.] Compared to a loop filter, it can be configured to average or filter over a longer period of time.

The replacement value provider is the quantity of the loop filter, such as an amount derived from the timing error information (eg, an intermediate internal or intermediate amount available within the loop filter or the sample timing information provided by the loop filter). Output], and/or timing error information and/or sample timing information provided by the loop filter by means of equal or different weights for the input values.

The replacement value provider may be configured to perform averaging with equal weights of the timing error information, or a quantity derived from the timing error information.

The replacement value provider is an amount derived from the timing error information to perform filtering or averaging on selected samples [so that the replacement value provider evaluates fewer samples per unit time than the loop filter] [eg, A time interval greater than or equal to the intermediate internal or intermediate amount available within the loop filter or the output of the loop filter, such as the sample timing information provided by the loop filter, or the samples of the timing error information. and a quantity derived from the timing error information (temporal spacing), or samples of the timing error information (associated with specific snapshots).

The replacement value provider provides the timing error information [eg, an intermediate internal or intermediate amount available within the loop filter or provided by the loop filter to perform filtering or averaging on the selected samples. The signal to adaptively select samples (eg, associated with specific snapshots) of the amount of timing error information, or an amount derived from the output of the loop filter, such as the sample timing information. Configured to perform analysis of [for example, a signal derived from the input signal or the input signal],

The receiver is configured to increase the number of selected samples for signals with relatively high noise and/or decrease the distance between the selected samples when compared to signals with relatively low noise.

The replacement value provider provides the timing error information to perform filtering or averaging on the selected samples so as to increase the average gain over average depth or filter length[ For example, an amount of the internal or intermediate amount available in the loop filter or the amount derived from the output of the loop filter, such as the sample timing information provided by the loop filter, or of the timing error information. It may be configured to adaptively select samples (eg, associated with specific snapshots).

The replacement value provider may perform the filtering or averaging for the downsample version of the timing error information [eg, associated with certain snapshots, eg, adaptively] [eg, A quantity derived from the output of the loop filter, such as an intermediate internal or intermediate amount available within the loop filter or the sample timing information provided by the loop filter, or a down-sampled version of the timing error information It can be configured to use [eg, a lower sampled version].

The replacement value provider is configured to perform the filtering or averaging on the downsample version by the timing error information [eg, by an intermediate internal or intermediate amount available within the loop filter or by the loop filter. An amount derived from the output of the loop filter, such as the sample timing information provided, or a down-sampled version of the timing error information (eg, the output of the TED) [eg, a sub-sampled version] Configured to use [eg, associated with certain snapshots, eg adaptively],

Thus, the sampling rate [or sample rate] of the down-sampled version is determined by the timing error information [eg, an intermediate internal or intermediate amount or loop available within the loop filter. An amount derived from the output of the loop filter, such as the sample timing information provided by a filter, or between 100 and 10000 times or between 500 and 2000 times slower than the sampling rate [or sample rate] of the timing error information. Is the first sampling rate.

The replacement value provider is the replacement value provider to perform filtering or averaging by at least 2 times or 8 times or at least 16 times or at least 32 times or at least 64 times and/or at least a factor of a power of 2 Derived from the timing error information processed by [eg, the intermediate internal or intermediate amount usable within the loop filter or the output of the loop filter as the sample timing information provided by the loop filter] It can be configured to change the rate of positive, or samples of the timing error information (eg, adaptively, eg, adaptively) to certain snapshots [eg, independently of other criteria. Or independently of the signal to noise ratio of the input signal] [eg, the total number of samples used by the replacement value provider to provide current replacement sample timing information may be constant].

The replacement value provider is between a low sampling rate and a high sampling rate [the sampling rate is configurable and/or controlled, and the bottom of it is configured taking into account at least one condition, eg, maximum lighting time] The timing error information [eg, the intermediate internal or intermediate amount available in the loop filter or the sample timing information provided by the loop filter to perform filtering or averaging on the selected samples. And an amount derived from the same output of the loop filter, or samples of the timing error information (eg, associated with specific snapshots) may be configured to be adaptively selected.

The replacement value provider is configured to provide the replacement timing information such as the timing error information [eg, an intermediate internal or intermediate amount available within the loop filter or the sample timing information provided by the loop filter. Configured to selectively consider [eg, process, or average, or select] samples derived from the output of the loop filter, or samples of the timing error information (eg, associated with specific snapshots) Can be,

As such, the current replacement timing information is such that the input signal is subject to the predetermined condition (eg, different values and/or different time periods associated with different time periods, such as filter outputs associated with different time periods or average). Skips a time period that is not achieved and lies between two different considered time periods, while the input signal has a predetermined condition (eg, the predetermined requirement or other requirement) Can be obtained based on samples of at least two different considered time periods of the input signal while satisfying.

The replacement value provider is based on a look-up table and/or configuration data according to a configuration according to a communication scenario, to the timing error information [eg, an intermediate internal or intermediate amount available in the loop filter or the loop filter. [Eg, adaptive] to select a quantity derived from the output of the loop filter, such as the sample timing information provided by, or samples of the timing error information (eg, associated with specific snapshots) Enemies].

The replacement value provider is for the derivation of the replacement sample timing information based on an analysis of the timing error information, or an amount derived from the timing error information [eg, by correlation and/or autocorrelation], An amount derived from the timing error information (eg, the internal or intermediate amount available within the loop filter or the output of the loop filter, such as the sample timing information provided by the loop filter), or It may be configured to adaptively select samples of the timing error information (eg, associated with specific snapshots).

The replacement value provider

Target signal-to-noise, SNR, ratio;

Supported timing offset range;

Supported carrier frequency offset range;

Convergence rate requirements;

The scheme used for detecting the time error;

Data signal features;

The timing error information to perform filtering or averaging on selected samples based on at least one or a combination of a used roll-off of a receiver-side matched filter and/or a used roll-off of a transmitter-side pulse-shaping filter [ For example, an amount of the internal or intermediate amount available in the loop filter or the amount derived from the output of the loop filter, such as the sample timing information provided by the loop filter, or of the timing error information. It may be configured to adaptively select samples (eg, associated with specific snapshots).

The receiver can be configured to increase the loop filter characteristics and/or the loop gain for an initial transitory interval.

The receiver is configured to re-configure the loop gain/loop filter characteristics while operating based on modified reception conditions (eg, lower SNR than before).

The receiver increases the loop filter characteristics and/or the loop gain of the loop filter for a signal with a relatively high SNR in relation to a signal having a relatively low signal to noise ratio (SNR). And/or to reduce the loop filter characteristics and/or the loop gain of the loop filter for signals with a relatively low SNR relative to the signal with a relatively high SNR.

The receiver includes a feedback mode in which the feedback signal is provided to the adjustable sample provider from the feedback path, and a replacement value providing mode in which the replacement sample timing information is provided to the adjustable sample provider, and

Intermediate values are configured to switch between intermediate modes provided to the tunable sample provider-the intermediate values are the values of the feedback signal and the replacement sample timing information [eg, average values ] Is obtained as values between -,

The transition from the feedback mode to the intermediate mode and from the intermediate mode to the replacement value providing mode, and/or

The transition is a transition from the replacement value providing mode to the intermediate mode and from the intermediate mode to the feedback mode.

The receiver may be configured to provide intermediate replacement sample timing information to smooth transition from the feedback mode to the replacement value providing mode, or vice versa, in the intermediate mode.

The receiver may be configured to provide reconstruction information and/or data from the replacement value provider 640 to the loop filter [eg, to avoid control signal jumps and as a baseline to avoid control signal jumps. To continue adaptive and/or interpolation with values].

In a controller (e.g., controller unit) for recognizing a transmission to be received,

The controller is limited by the amount derived from the power [eg, a low-pass filtered version of the power level information], or by an interval in which the power of the received signal is limited [eg, a lower interval boundary value and an upper interval boundary value. felled; This may, for example, make a determination as to whether or not it lies within “power range” or “power level” identification), and the determination [amount derived from the power, or the power of the received signal is limited. Can be configured to recognize a transmission to be received based on whether it lies within an interval [the above limited interval can be dynamically defined, for example] [eg, at least one power level is at least two Successive power samples can be dynamically defined based on the determination that they lie within limited intervals with respect to a particular power level].

The controller may be configured such that the received signal has a power level previously determined [eg, power niveau] [eg, among two or more power levels to be distinguished-the at least two or more power levels or nives are different. Signal content, other beams, which may be associated with different receivers-].

The controller at least while the received signal includes a power level (eg, by counting the number of consecutive samples at the same power level and/or by analyzing the time distance between samples within a predetermined search time period). From the received signal (eg, a low pass filtered version of the power level information) to recognize the length of one limited time period [eg, the length of the signal burst, or the length of the lighting in a particular spatial area] The amount derived, or further configured to determine how long the power of the received signal lies within the limited interval [the limited interval can be dynamically defined, for example] [eg, at least One power level can be dynamically defined based on the determination that at least two consecutive power samples lie within constrained intervals with respect to a particular power level.

The controller supports the recognition of the transmission to be received (eg, by allowing it to recognize the wrong decision), so that the recognized length of the limited time period while the received signal includes the power level is preset. It may be configured to check whether the determined condition (eg, at least approximately multiple scheduling granularities, or following a time schedule of a given transmission among a plurality of different transmissions) is satisfied.

The controller is an amount derived from the power [eg, a low pass filtered version of power information], or different power levels of the received signal [eg, one of the two or more different power levels is noisy It may be a power level and two or more power levels may be related to different beams or different transmissions] may be further configured to recognize (eg, distinguish).

The controller may be configured to track the duration at which the different power levels appear, to derive scheduling information [eg, a plurality of samples within a predetermined search time period to recognize a specific power level is specified power range Configured to recognize being within.

The controller can be configured to check whether the current power level lies in a limited interval and interval boundaries determined based on the previously derived power level scheduling information.

The controller can be configured to selectively switch the receiver or its components to a reduced power consumption mode based on the derived scheduling information [eg, based on the derived scheduling information, to be received by the receiver For periods of time that are estimated to have no transmission] [When the transmission to be received is expected based on the derived scheduling information, the receiver can also switch back from the reduced power consumption mode to a “normal” reception mode. have].

The controller ranks the different time periods (eg, which periods of time have the highest power level, second highest power level, etc.) to recognize the time periods for the transmission to be received. In order to recognize the periods of time during which the different power levels and the different power levels of the amount derived from the received signal, or from the power (eg, a low pass filtered version of the power information) [Eg, by selecting a time period during which there is a peak power level].

The controller may select the time period having a relatively high power level [or a relatively highest power level] in relation to a time period having a relatively low power level, or the power of the received signal [eg, Low pass filtered version of power information].

The controller is configured to store time information characterizing (or describing) time parts of different levels of the received signal and the power (eg, a low-pass filtered version of the power information). It can be configured to store information about the power level of the received signal or the amount derived from,

At the next moments, it is configured to recognize time periods associated with the transmission to be received, at least based on the stored time information.

The controller may also use the stored information for the power level of the received signal during different time portions for the recognition of the time periods associated with the transmission to be received (eg, to set interval boundaries). Can be configured.

The controller may be configured to determine the start and/or end of a period of transmission to be received based on the power level (eg, a low pass filtered version of power information).

The controller decodes at least one piece of information (eg, sequence and/or preamble and/or specific bit stream) encoded in the received signal to determine the start and/or the end of the period of transmission to be received ( decode) and/or detect (eg, both the power level and the decoding can be used, and the transmission to be received is already recognized even if the power is still not within the limited interval when characteristic information is decoded) Can be.].

The controller may include an upper interval boundary value and/or a lower interval boundary value and/or time information associated with at least one power level [eg, range] [eg, scheduling related and/or BTSP related information and/or modification] With respect to] it can be further configured to receive signaling transmissions from the transmitter. [For example, the controller configured to acquire signaling transmissions to at least partially be controlled by the signaling transmissions or to obtain side-information].

The controller may be configured to recognize the start and/or the end of the period of the transmission to be received by redundant or supporting technology including at least one of the following (or a combination of at least two): Can:

Detecting whether the slope in the power is above or below a predetermined threshold (eg, the detected increase in power of the received signal over time is faster than the lower limit) By determining that it is greater than an upper threshold indicating an increase and/or a negative increment in the detected power of the received signal over time indicating a rapid decrease in the detected power By determining that it is lower than a negative lower threshold];

Using time information obtained with previous power level determinations [eg, to predict the time at which the transmission to be received is expected to start using time extrapolation];

o decoding [or detecting] specific information encoded in the received signal (eg, sequence and/or preamble and/or specific bit stream); And/or

o detecting quality information [eg, signal to noise ratio] or inferring it from other modules (eg, signal to noise ratio estimator); And/or

o Using commands and/or signaled data from the transmitter.

[To check the accuracy of the decision based on the power level based on the unnecessary/supporting technology above].

The controller can be further configured to dynamically define and/or recognize at least one power level based on the determination that at least two consecutive power samples lie within limited intervals associated with a particular power level.

], 및The controller, as a first condition, is within an interval determined by the first sample of the positive, derived from the power, or the current sample of the power of the received signal, of the positive, or of the received signal of power. To determine whether it lies (eg, an interval extending upwards and downwards from the first preceding sample value), and as a second condition, the current sample of the positive, or the power of the received signal derived from the power is also the And may be configured to determine if it lies within an interval determined by a second preceding sample of the power, or of the received signal derived from power (eg, an interval extending up and down from the second preceding sample value). [For example,

], and

The controller may be configured to recognize a continuity of power levels when both the first condition and the second condition are satisfied.

The controller is a continuous number of a predetermined number of the positive, or the predetermined number of the power of the received signal derived from the power that does not satisfy the first condition and/or the second condition without recognizing the end of the power level. Can be configured to tolerate samples (eg, 1 sample),

Configured to recognize the end of the power level if the positive, or successive samples of the power of the received signal derived from a greater number of the power than a predetermined one do not satisfy the first condition or the second condition Can be.

The controller is the amount derived from the power (eg, a low pass filtered version of the power level information), or the amount of the current sample of the power of the received signal derived from the power, or the received It may also be configured to determine whether it lies outside of a tolerance interval (described by “additional thresholds”) that is greater than the interval determined by the immediately preceding sample of the signal,

The controller may allow the current sample to be placed at least once outside of the interval determined by the immediately preceding sample without recognizing the end of the power level. It may be configured to recognize the end of the power level [immediately] when the current sample of the power is placed outside of the allowable interval for the first time.

The controller may be further configured to operate according to the first and second operation modes (eg, the second mode is initiated in response to the end of the first mode), and at least one of the first and second modes The controller in can be configured to perform a combination of at least two of the following techniques (optionally in combination with other techniques) or at least one of the following techniques (usable with other techniques):

-A technique for determining whether an amount derived from the power [eg, a low-pass filtered version of power information], or whether the power of the received signal lies within a limited interval;

-A technique to check if power is determined at the expected time period (eg, as extrapolated from previous measurements);

-A technique for decoding or detecting specific information (eg, sequence and/or preamble and/or specific bit stream) encoded in the signal to be received;

-Techniques for checking quality information (eg, signal to noise ratio);

-Technology for checking the satisfaction of the criteria according to information signaled from the transmitter;

A technique for detecting whether the slope in the power is above or below a predetermined threshold (eg, the detected increase in power of the received signal over time is the lower limit) ), and/or by determining that it is greater than an upper threshold indicating a fast increase and/or a negative increment in the detected power of the received signal with respect to time, resulting in a rapid decrease in the detected power. By determining that it is lower than the negative lower threshold indicated];

The controller may be configured to use at least one different technique in the first mode in relation to the second mode.

The controller can be further configured to operate in accordance with at least two modes of operation:

The amount derived from the power [e.g., a low-pass filtered version of the power information] without the controller taking into account the information encoded in the signal, or the interval at which the power of the received signal is limited [eg , Based on power measurements]. And

The controller determines whether the amount derived from the power [eg, a low pass filtered version of power information], or the power of the received signal lies within a limited interval, and

A second mode that verifies the accuracy of the decision based on whether the encoded information in the received signal conforms to the recognition of the transmission to be received based on the power (eg, corresponds to the end of the first mode) Initiated by].

The controller may be further configured to derive or obtain an amount derived from the power (eg, a low-pass filtered version of power information) from automatic gain control (AGC).

The controller can be further configured to derive an amount associated with the power [or derived from the power] (eg, a low-pass filtered version of the power information) from a matched filter.

In the above and/or below controller, the amount associated with the power (or derived from the power) may be an infinite impulse response (IRR) filtered version of the power information.

The controller can be further configured to perform an initialization procedure to obtain parameters related to at least one or a combination of the following:

Power for determining at least one power level to be used later to recognize a transmission to be received (eg, limited by a lower boundary value and an upper boundary value);

Time information (eg, time moments and/or scheduling information at which different power levels are detected);

Quality information [eg, signal to noise ratio];

The controller time progress of the positive or the power derived from the power over the period of the received signal to receive the signaled information to perform the initialization, or to perform the initialization (temporal evolution).

[For example, the parameters can be obtained by receiving and/or measuring information signaled from the receiver].

The controller has an upper interval boundary value and a lower interval value for the power (and/or other parameters related to the transmission to be received) based on the historical values of the power. boundary value).

The controller can be configured to control any of the above and/or below at least one of the receivers.

The controller includes a first state [eg, feedback state] in which the feedback path provides the feedback path to the adjustable sample provider; And

A second state where the replacement value provider provides the replacement sample timing information to the adjustable sample provider [eg, freeze state]

It can be configured to control at least one of the above or below the receiver to choose from.

The controller is based on the predetermined requirement to be satisfied by the input signal [eg, a power and/or power level associated with the input signal and/or a specific sequence encoded in the input signal, eg, with an illumination member It may be configured to control at least one of the above or below receiver to determine the relevant requirements.

The controller providing the feedback signal 638 to the adjustable sample provider 604 when the feedback path 630 recognizes that the controller unit 650, 654 will receive the transmission; And/or

The replacement sample timing information 642 is adjusted by the adjustable sample provider 604 when the replacement value provider 640 recognizes that the controller unit 650, 654 is not a transmission to be received or there is no transmission. )

It can be configured to control at least one of the above or below the receiver to select.

The controller may further include the above and/or below controllers.

A transmitter and a receiver, wherein the receiver (e.g., having multiple receiving antennas) is the receiver as above or below, and the transmitter is a signal to the receiver (e.g., beam-formed) formed) or beam-switched signal].

The transmitter may be a satellite (eg, in amplification and forward mode or in signal processing and forward mode or in signal generation mode).

The transmitter may be configured to perform transmission according to a beam-switching time plan (BSTP) transmission and/or according to a scheduling transmission,

The BSTP and/or the scheduling can be defined such that the signal is intended to be transmitted to the receiver for at least one first interval, and the signal is not intended to be transmitted to the receiver for at least one second interval. have.

The system further comprises a plurality of receivers, the transmitter being configured such that a specific beam is directed towards the intended receiver in accordance with BSTP and/or scheduling so that the signal power is temporarily improved in the direction of the intended receiver. Can be.

The receiver may use the feedback signal in determining that the transmitter is directed to the receiver, and in determining that the transmitter is not intended for the receiver and/or in the non-determination of transmission from the transmitter. It can be configured to use replacement sample timing information.

The transmitter at least according to a continuous signal condition in which the beam is continuously directed to the receiver, and a bursty signal condition in which different beams are directed to different receivers (eg, according to scheduling or BSTP). It can be configured to operate.

The method for receiving the input signal,

Processing (eg, by timing interpolation) samples of the input signal using adjustable sample timing (eg, determined by sample timing information);

Adjusting the sample timing based on a feedback signal (eg, TED, loop filter) based on a timing error (eg, determined by a timing error detector)-the feedback signal is a loop filter providing sample timing information Obtained using -; And

The input signal is a predetermined requirement for feedback-based sample timing adaptation [eg, based on a specific sequence encoded in the input signal and/or based on a power level and/or power associated with the input signal, a controller Providing replacement sample timing information that replaces the sample timing information provided with the feedback signal when it does not meet the requirements associated with the absence of lighting and/or based on the control exerted by And

The replacement sample timing information is obtained by taking into account the amount derived from the timing error information, or timing error information, over a longer time period when compared to the time period considered by the loop filter to provide the sample timing information. Lose.

The method for receiving the input signal,

Processing (eg, by timing interpolation) samples of the input signal using adjustable sample timing (eg, determined by sample timing information);

Adjusting the sample timing based on a feedback signal (eg, TED, loop filter) based on a timing error (eg, determined by a timing error detector)-the feedback signal is a loop filter providing sample timing information Obtained using -; And

The input signal is a predetermined requirement for feedback-based sample timing adaptation [eg, based on a specific sequence encoded in the input signal and/or based on a power level and/or power associated with the input signal, a controller Providing replacement sample timing information that replaces the sample timing information provided with the feedback signal when it does not meet the requirements associated with the absence of lighting and/or based on the control exerted by And

The replacement sample timing information temporarily smooths the sample timing information provided by the loop filter to obtain the replacement sample timing information (eg, low-pass-filter order time average). It is obtained by.

The method for recognizing the transmission to be received is:

An amount derived from the power [eg, a low pass filtered version of power information], or the power of the received signal is limited by a limited interval [eg, a lower interval boundary value and an upper interval boundary value; This can, for example, constitute an identification of “power range” or “power level”] determining whether it lies within, and

And recognizing the transmission to be received based on the determination.

Way:

Can include any of the above and/or following methods,

The provision of the replacement sample timing information in the above and/or the following method and the provision of the feedback signal can be controlled by the above and/or the following methods.

A computer program that, when executed by a processor, performs at least one of the above and/or below methods.

Figure 1: Example of a system with a transmitter and receivers. Time slots are distributed to different service areas through a beam-hopping satellite system.
2A and 2B: Terminal-side receive signal scenarios with multiple illuminations.
Figure 3: Timing loop with the addition of a freezing controller according to the prior art
Figure 4: Power detection using a threshold-based detector that evaluates min/max power.
Figure 5: Power detection using a slope based detector.
Fig. 6: Block scheme of receiver signal processing of a receiver showing a freeze controller for evaluating power detection data and timing loops, especially for calculating replacement values.
Fig. 6a: Flow chart of timing loop
6B: Filtering and/or averaging according to an example
Figure 6c: shows components according to an example.
Fig. 6d: shows a variation of the example of Fig. 6;
Figure 6e: shows an example of a receiver.
Figure 7: Power detector using power level detection.
7A: Enhanced power detection and analysis by means of additional threshold checks to identify significant changes in power.
Figure 7b: Example of power level
7C: Method according to an example
7D: Table stored in a memory unit according to an example
Figure 8: Block scheme of components of receiver signal processing of the receiver. The component includes a “Framing Verification and Correction” block after the “Preamble Detector” module in the “Further data processing” block.
9 and 10: Different detection cases of a correct frame.

Explanation

In the following, different original embodiments, examples and aspects will be described.

In addition, additional embodiments will be defined by the appended claims.

The embodiment defined by the claims can be supplemented by any details (features and functions) described in the next chapter.

The embodiments described in the following chapters may be used individually and may be supplemented by any of the features of any other chapter or any feature included in the claims.

The individual aspects disclosed herein can be used individually or in combination. Thus, details can be added to each of the individual aspects mentioned without adding details to one of the other mentioned aspects.

The present disclosure explicitly or implicitly describes the characteristics of mobile communication systems and receivers and mobile communication devices. Thus, any of the features described herein can be used in connection with a mobile communication system (eg, including satellites) and in connection with a mobile communication device. Accordingly, the disclosed techniques are suitable for all fixed satellite services (FSS) and mobile satellite services (MSS).

Furthermore, the functions and features disclosed herein in connection with the method can be used in the device. Moreover, any functions and features disclosed herein in connection with the apparatus can also be used in a corresponding method. In other words, the methods disclosed herein can be supplemented by any of the above features and functions disclosed in connection with the devices.

Further, any of the above features and functions disclosed herein may be implemented in hardware or software or using a combination of hardware and software, as described in the “implementation alternatives” section.

Hereinafter, embodiments of the present invention may be referred to as examples.

Introduction

The wireless receiver must be synchronized with the received signal to decode. Timing loop is a method for synchronizing with continuous signals. However, burst signals can freeze loop-feedback when there is no signal.

The first part (first aspect) of the present invention relates to additional means for a feedback loop, for example, to improve open loop accuracy to achieve fast resynchronization with little or no offset result. Such an additional means may mean that the control of the loop feedback path according to the calculation and freezing of the correct replacement value at the numerically controlled oscillator (NCO) input is set to ON or OFF. A low complexity embodiment is proposed and demonstrated to achieve the same accuracy as an alternative large complexity embodiment.

The second part (second aspect) of the invention relates to, for example, how a freezing signal is generated. The generation of the freezing signal may be used independently of the first side or in combination with the first side. According to the present invention, a freezing controller may evaluate information from a power-level detection method and/or a known-sequence detector (eg, via correlation). Can be. With both knowledge and knowledge of burst-size granularity, the freezing controller can adaptively switch between continuous signal reception mode or burst signal reception mode. In the latter case, the two detection methods can be used to identify and schedule the appropriate configuration for a non-freeze or transition to freeze.

The third part (third aspect) relates to an auxiliary module for data frame synchronization. At the start of each bursty signal reception, it is possible to compensate and tackle problems due to fast timing loop resynchronization. There is uncertainty in very few symbols after the re-convergence of the timing loop and the uncertainty about the expected data framing grid. Therefore, this module “Framing Verification and Correction” can estimate and compensate for this offset.

Examples:

Innovative Aspect 1: Maintain sampling accuracy during adaptive freezing

1 and 2 have been used to discuss the prior art, they can also be used to describe the system 100 according to the present invention. Accordingly, the system 100 beams 120-124 in a time slot 120'-124' illuminated according to a super-frame defined by a transmitter (e.g., satellite 102), gateway 116. It may include receivers (eg, terminals) disposed in different coverage areas 104-108 to receive. The scenario of FIG. 2A can also occur. In addition to the intended beam C at power P2, the receiver can also receive a non-intended beam D intended to be received by a different receiver according to BSTP.

6E shows a receiver (eg, one of terminals 110, 112, 114). The receiver may include an antenna array 127 for performing transmission and/or reception. The antenna array 127 may be coupled to receiver signal processing 600 and/or transmit signal processing 600e. Receiver signal processing 600 and/or transmission signal processing 600e may be connected to an input/output port 129 that may be connected to external devices and/or application-running equipment (in some cases, Application execution equipment may be integrated into the receiver and/or the processes (600 or 600 e).

Each receiver may include hardware and functional means (eg, antennas and/or antenna arrays, communication controllers, digital signal processors, etc.) to perform processing 600.

The signal processing 600 (which may be implemented with any of the remote terminals 110-114 of the present invention) is input with the signal 602 (which can be obtained from any beam 120-124). do. Signal 602 is processed to be provided to data processing block 620. The processing block is, for example, an adjustable sample provider 604 (eg, a timing interpolator), a matching filter 608, an automatic gain control block 612, a selector 616 ( In an alternative embodiment, one or some of these blocks can be avoided). Matching filter 608 may be a low-pass filter (eg, a linear low-pass filter) that matches a transmit-side pulse-shaping filter. Therefore, a signal to noise ratio (SNR) may be maximized according to communication theory. The automatic gain control (AGC) 612 can analyze the signal power of the version 610 of the input signal 602 (eg, as output by the matched filter 610). AGC 612 can scale the signal to achieve a target power level at its output (version 614 of input signal 602). Optional selector 616 may drop samples of version 614 of input signal 602 every second (other types of selectors may be defined in alternative embodiments).

Also provided is a feedback path 630 (with a timing error detector, TED 632, and loop filter 636) and a replacement value provider 640.

ller&M

ller detector)를 포함할 수 있다. TED (632)는 검출된 순간 타이밍 오프셋과 관련될 수 있는 타이밍 에러 정보 (634)를 출력할 수 있다. TED 632 can, for example, obtain an instantaneous timing offset from samples. TED 632 is, for example, an early-late detector, a zero-crossing detector and/or a Müller&Muller detector (M)

ller&M

ller detector). The TED 632 may output timing error information 634 that may be associated with the detected instantaneous timing offset.

The loop filter 636 can perform operations such as averaging, scaling and/or integration. The setting of the low-pass filter can be a low-pass filter that controls its loop convergence and tracking characteristics. The loop filter 636 can provide feedback-based information 638 that takes into account timing errors based on, for example, timing error information 634.

The loop filter 636 can perform a relatively small weighting averaging or equally or exponentially weighted averaging for past input values when compared to current input values. The output 638 of the loop filter 636 (referred to herein as “sample timing information”) may indicate a smoothed and integrated version of the timing error information 634. Sample timing information 638 may be the feedback-based information used by the adjustable sample provider 604 to compensate for synchronization errors. The sample timing information 638 can take into account the filtered value or the average value calculated over a specific period (eg, a determined period related to the final number of K samples).

According to an aspect of the first invention, during a non-illumination time period, the timing interpolation is performed using a replacement value 642 without using feedback values as in FIG. 3 (prior art). When lighting ends (eg, at 120b, 122b, 124b), signal processing 600 is unlikely to obtain reliable timing error information from feedback path 630 (and thus will be based on noise). If the prior art teachings have to be followed, the last timing will be used and freezed over the entire non-lighting cycle. Note, however, that there is no guarantee that the last timing is sufficiently accurate or correct. By freezing the last timing, there is a possibility that a large timing error accumulates throughout the entire non-lighting period. However, in the aspect of the present invention, at the end of illumination (e.g., at 120b, 122b, 124b), the last timing is not freezes, but instead the replacement value 642 (usually calculated over a longer period of time and thus As a rule, correct) is used, reducing the possibility of incorrect timing.

Basically, in this aspect of the invention, the feedback strategy is activated in the most convenient case (during a lighted time period), while the feed forward strategy is activated in the most convenient case (during an unlit time).

The adjustable sample provider 604 (timing interpolator) can provide samples of the input signal 602 using adjustable sample timing. The adjustable sample provider 604 can resample the received input signal 602 to allow decoding, demodulation and synchronization of data encoded in the input signal 602. Therefore, the timing offset (sampling phase and sampling frequency) can be compensated.

Accordingly, the adjustable sample provider 604 can rely on the feedback path 630, which provides feedback-based information 638 for previously occurring timing errors (sample timing information) in real time. Can be.

The feedback path 630 may include a timing error detector (TED) 632 that derives a timing error value based on previous portions of the input signal 602 (previous samples, etc.), for example. have. Therefore, timing error information 634 can be provided by TED 632.

However, according to aspects of the present invention, signal processing 600 does not uniquely use feedback path 630.

Signal processing 600 can include a replacement value provider 640 that can provide replacement sample timing information 642 (eg, for the purpose of replacing sample timing information 638 during a non-lighting cycle). . Thus, at some moments, while replacement value provider 640 is active, feedback path 630 can be deactivated, and vice versa. Timing interpolator 604 alternatively:

Sample timing information 638 (obtained from feedback path 630 and based on error information damaging previous samples), eg, according to a feedback technique, and

Replacement sample timing information 642 (obtained from replacement value provider 640) may be used, for example, according to a feedforward technique.

This selection between two alternative timings is represented by selector 644 in FIG. 6.

For bursty signal receptions (eg, in non-continuous lighting environments such as FIGS. 1 and 2), during non-lighting periods, replacement sample timing information 642 is provided to timing interpolator 604 Whereas, sample timing information 638 can be provided to the timing interpolator 604 during an illuminated time period.

More generally, replacement sample timing information 642 may be provided to timing interpolator 604 when a predetermined requirement is not achieved (which may be a requirement to determine whether an input signal is received). The above requirements may be related to, for example, the presence of lighting and/or control exerted by the controller, e.g., in the input signal 602 (e.g. in the initial part of the frame associated with the input signal). ) Can be based on the determination of the power level and/or power associated with a particular encoded sequence (eg, pilot sequence and/or preamble) and/or input signal.

Thus, the receiver's processing 600 may have at least two modes (three modes in some optional examples):

-A feedback mode in which the feedback path 630 is activated and provides sample timing information 638 to the timing interpolator 604 (e.g., feedback mode achieves predetermined requirements, such as the presence of lighting, for example) Related to);

-Sample timing information 638 is deactivated and replacement sample timing information 642 actively provides replacement sample timing information 642 to timing interpolator 604 (eg, according to feedforward technology A replacement value provision mode (which operates), wherein the replacement value provision mode is related to, for example, non-fulfilment of predetermined requirements, and thus to the absence of lighting. May be);

-(Optionally) intermediate mode (see below).

The replacement timing information 642 includes timing error information 634 such as intermediate information (eg, inside the loop filter 636) or sample timing information 638 provided by the loop filter 636. It can be generated by the replacement value provider 640 based on timing error information 634 or quantity obtained from.

However, the replacement sample timing information 642 takes into account the amount or timing error information 634 derived therefrom over a time period longer than the time period considered by the loop filter 636 when providing the sample timing information 638. Can be created by

Additionally or alternatively, the replacement value provider 640 provides loop filter-internal timing information and/or sample timing information 638 provided by the loop filter 646 to provide replacement sample timing information 642 Can be configured to temporarily smoothen (eg, a low pass filter or time average).

It has been noted that by using more accurate replacement sample timing information 642 during the non-illumination cycle, jitter is reduced when the illumination is restarted. During a non-lighting cycle, the last value of the output (634 or 638) is actually no longer used (after being frozen). Conversely, during non-illumination periods, taking into account historical data, a value 642 that is the result of a longer time-based averaging or filtering can be used. For example, during non-illumination cycles, it is less likely that incorrect timing information will accumulate. Otherwise, by freezing the final value 634 or 638 as in the prior art, greater jitter will accumulate in the timing interpolator 604.

The replacement value provider 640 may take into account the values of the timing error information 634 (or 638) over the first period to provide current replacement sample time information. The loop filter 636 can take into account the values of the timing error information 634 over a second period shorter than the first period to provide current sample time information 638. Thus, the replacement sample timing information 642 is generally based on a larger time period, resulting in less random errors and generally more reliable.

The replacement sample timing information 642 can be derived by a loop filter 636 over a period longer than the period for which the timing error information 634 is considered to provide the current sample timing information 638 [eg. , Time period considered by loop filter for providing sample timing information] [eg, filter length of FIR filter used as loop filter].

In some examples, the impulse response of replacement value provider 640 for the value of information 634 (or 638) is longer than the impulse response of loop filter 636 for the value of timing error information 634 (or 638). .

The replacement value provider 640 can perform linear averaging by the same or different weights.

An example of a technique for obtaining replacement sample timing information 642 is provided here.

It is conceivable that the replacement value provider 640 generates replacement sample information 642 by averaging values 634 (or 638) over an extremely extended time period (and a very large number of samples) on a large scale. However, it has been found that it is advantageous for the replacement value provider 640 to reduce complexity and memory requirements by considering only a selected number of samples per unit time. The selected samples will be averaged or filtered by the replacement value provider 640, but unselected samples will not be used by the replacement value provider 640.

For example, the replacement value provider 640 can select samples with greater temporal spacing than the samples of information 634 or 638. The replacement value provider 640 can evaluate fewer samples per unit of time than the loop filter. Thus, the computational effort required to generate the replacement sample timing information 642 is not excessive, but the replacement sample timing information 642 still provides historical information compared to the values provided by the loop filter.

For example, the replacement value provider 640 may use a down-sampled version of the information 634 (or 638) instead of all samples of the information 634 (or 638) (e.g., a sub-sampled version). version)) to generate replacement sample timing information 642. For example, the replacement value provider 640 may average (or perform filtering to account for) a specific percentage of the sample of information 634 (or 638) while discarding other samples. The downsampled version of the information 634 (or 638) may have a first sampling rate of 100 to 10000 times, or 500 to 2000 times slower than the sampling rate of the information 634 or 638. For example, the replacement value provider 640 can change (down-sample) the rate of samples of information 634 or 638 by factor of 2, thus generating replacement sample timing information 642 and Therefore, one of the two samples is discarded. In other examples, the rate of samples may vary by 8 times or at least 16 times or at least 32 times or at least 64 times and/or at least a factor of a power of 2.

The replacement value provider 640 can adaptively select a sample of timing error information 634 to perform filtering or averaging on a sample selected between a lower sampling rate and a higher sampling rate.

It has also been noted that the replacement value provider 640 can adaptively select the number of samples of the information 634 (or 638). Thus, the distance between two consecutive selected samples of information 634 (or 638) is performed on the input signal 602 (or, for example, on any of the information 606, 610, 634, 638). It can be increased or decreased based on the decision. For example:

-If the input signal is noisy, the distance between the selected information samples 634 (or 638) to calculate the sample timing information 642 will be reduced (e.g., high noise, the downsampling coefficient is small) , For example 2 or 4);

If the input signal is noise-free, the distance between the selected information samples 634 (or 638) to calculate the sample timing information 642 will be increased (eg, if the noise is low, the down-sampling coefficient is Large, for example, 32 or 64).

Therefore, there may be a measurement of the fly of the SNR of the received signal. The higher the SNR, the lower the downsampling rate. Therefore, the more noise in the input, the shorter the distance between the samples used.

If the input signal 602 is noisy, the information 642 that can be obtained can in principle be assumed to be non-particularly reliable. To cope with this problem, the replacement value provider 640 increases the number of samples per unit of time to be averaged so that the resulting information 642 is based on more samples. Thus, for noisy signals, the replacement value provider 640 may consider a more increased number of samples for signals with less noise per time unit.

In general, it is possible to perform different downsampling techniques to obtain the information 642, depending on the signal-to-noise ratio of the input signal or other criteria. For example, the lower the signal to noise, the higher the ratio, the higher the downsampling.

In examples, filtering or averaging for selected samples is the target signal-to-noise, SNR, ratio, supported timing offset range, supported carrier frequency offset range, convergence rate requirements, scheme used for time error detection. , Data signal characteristics, used roll-off of the transmit-side pulse-shaping filter and/or used roll-off of the receiver-side matching filter 608 It can be performed by the replacement value provider 640 based on either or a combination of.

The replacement value provider 640 may have, for example, signal processing capabilities and/or to optimize downsampling, for example, information 634 or by correlation and/or autocorrelation. 638), and the signal-to-noise ratio can be calculated.

In particular, however, it is generally not to indefinitely up-scale the distance between two successive selected samples of information (634 or 638) (or to indefinitely sample the rate of information (634 or 638)). It is preferred). Indeed, samples that replacement value provider 640 must average or filter must be obtained during illumination time. Therefore, the maximum distance is defined. Thus, the sampling rate of the information 634 or 638 (as input to the replacement value provider 640) is configured and/or configured such that its bottom is configured taking into account the maximum and minimum lighting times (other conditions can be defined). Or it may be controllable. Thus, it is ensured that the replacement value provider 640 does not attempt to acquire samples of the information 634 or 638 only during a non-lighting period.

The replacement value provider 640 can average or filter samples of at least two different time periods of the input signal 602 where the input signal satisfies a predetermined condition (e.g., a predetermined condition such as the presence of lighting). have. At least some of the samples of information 634 or 638 considered by the replacement value provider 640 may be taken from different lighting periods. The replacement value provider 640 does not consider non-illuminated time period samples.

In examples, samples of information 634 or 638 may be selected based on lookup table and/or configuration data depending on the communication scenario or configuration.

As described above, receiver signal processing 600 can have at least two or three modes:

-The feedback mode in which the sample timing information 638 of the feedback path 630 is activated,

-The replacement value providing mode in which the sample timing information 638 is deactivated (replacement information 642 may be provided in turn),

-(Optionally) the intermediate mode.

An intermediate mode may be provided to avoid hard-switching when transitioning from the replacement value providing mode to the feedback mode. Process 600 may operate as follows:

-In order to transition from the feedback mode to the replacement value providing mode (for example, when lighting is terminated):

o transitioning from the feedback mode to the intermediate mode; And, next,

o transitioning from the intermediate mode to the replacement value providing mode, and/or

-To transition from the replacement value providing mode to the feedback mode (e.g., when lighting is determined):

o transitioning from the replacement value providing mode to the intermediate mode, and, next,

o Transitioning from the intermediate mode to the feedback mode.

Processing 600 may be configured to smooth transitions, for example, by avoiding “jumps” or by performing interpolation and/or adaptation with replacement values as a baseline. As shown in FIG. 6, in intermediate mode, a value 646 (which may be a version of replacement sample timing information 642) can be provided to the loop filter 636, thus replacing the value 646 ( Alternatively, the replacement value 646 and the intermediate value of the value 634) may be filtered and the filtered value may be provided to the timing interpolator 604 as sample timing information. The value 646 can be an example of the reconstruction information provided to the loop filter 646 for the intermediate mode by the replacement value calculator 640.

Additionally or alternatively, the loop gain associated with the loop filter 636 may be increased and/or the loop filter characteristics may be modified during the initial transient interval at which the loop filter 636 is modified. In some cases, if the SNR is detected to be reduced compared to the previous SNR, the loop gain may be increased or the loop filter characteristics may be modified. For example, a loop filter characteristic of the loop filter 636 for an input signal having a relatively higher SNR with respect to a signal having a relatively lower signal to noise ratio, SNR (e.g., wider low pass bandwidth) ) And/or increasing the loop gain, and/or the loop filter characteristic of the loop filter (e.g., for an input signal with a relatively lower SNR relative to a signal with a relatively higher SNR) For example, it is possible to change the smaller low pass bandwidth) and/or reduce the loop gain.

In examples, activation of the feedback mode and the replacement value providing mode (and/or in some examples, transition through the intermediate mode) is performed by a freezing controller 650 that can operate based on power information 656 ( For example, by recognizing lighting or non-lighting conditions).

6A shows a view 690 showing the operation along side 1. Freezing controller 650 checks whether a light is present (eg, it may be a predetermined requirement), for example, by detecting whether the start of the light has occurred. When lighting begins, steps 692-696 of feedback mode 698 are invoked. Feedback processing is activated in these steps 692-696. At 692, an input signal 602 is obtained. Then, at 693, the sample timing information 638 is updated by the feedback path 630. In parallel (or serially in other examples), at 694, the replacement sample information 642 is updated by the replacement value provider 640 even if it is not currently output (updates are not activated in all cases; for example For example, step 694 is, for example, actually activated at a distance of 1000 snapshots based on the determined SNR, or other distances discussed above, for example). At 695, the timing is applied by an adjustable sample provider 604 to interpolate timing based on instantaneous feedback. At 696, the signal is decoded at block 620. In step 691b, if it is confirmed that there is no illumination (eg, by determining the end of the illumination), the replacement sample timing providing mode 699 (block 697) is entered, and the replacement sample timing information 642 is replacement sample timing information. Output is continuously performed to perform timing interpolation based on 642.

In particular, while the components 604, 608, 612, 616, 620 operate to allow decoding of data from the signal 602 under timing conditioned by the feedback path 630, the feedback mode 698 ) Can also be considered a normal receive mode. Conversely, the replacement sample timing providing mode 699 is a reduced power consumption mode in which the components 612, 616, 620 and/or the feedback path 630 are deactivated to reduce power consumption during non-lighting periods (reduced- power-consumption mode).

6B resumes operation according to the first aspect in the one-dimensional graph. The time axis is represented by a discrete sequence of samples i, each associated with a sample of timing error information 634 is used to generate sample timing information 638. Feedback mode 698 (during lighting) and replacement sample mode 699 (without lighting) are shown. When the normal moment is in feedback mode 695, loop filter 636 samples a small time period tsmall (e.g., formed by the last 32 samples of timing error information 634, denoted 62). The timing error information 634 is processed in proportion to the samples to obtain samples of sample timing information 638 to be provided to the adjustable sample provider or timing interpolator 604 (see step 693). At the moment, the replacement value provider 640 also processes the timing error information 634 to update the replacement sample timing information 642. Samples of timing error information 634 that are averaged by the replacement value provider 640 (eg, in step 694) are taken in a large time period (large> tsmall). However, as described above, however, not all samples in a large time period are processed by the replacement value provider 640. For example, only samples 60 having a relative distance (tsnapshot) (snapshot distance) can be selected. In particular, however, in feedback mode 698, samples of sample timing information 638 are provided to timing interpolator 604, while updates of replacement sample timing information 642 are output by replacement value provider 640. Does not work. In replacement sample mode 699, replacement value provider 640 and loop filter 636 do not perform any averaging or filtering. However, in replacement sample mode 699, replacement value provider 640 may continue to provide a constant value of replacement sample timing information 642 to timing interpolator 604, while timing from loop filter 636. Timing information is not provided to the interpolator 604.

In examples, averaging or filtering operations performed by loop filter 636 and/or replacement value provider 640 may be weighted. For example, closer samples can be weighted higher than farther samples. In other cases, the weights may be single and/or identical between samples.

As described above, the length of the tsnapshot can be adapted to the received signal 602. Noisy signals may require a smaller tsnapshot length. For example, therefore, the higher the SNR, the smaller the tsnapshot.

The replacement value provider 640 may also temporarily smooth the sample timing information 638 provided by the loop timing 636 to obtain more accurate replacement sample timing information 642 than the sample timing information 638.

The discussion of the operations described above is performed here.

Compared to the conventional approach of FIG. 3, the feedback path 630 has a larger bit and a module 640 for calculating the replacement value using the loop filter output (and/or TED output 634 in another embodiment). -Accuracy is improved by width. When freezing is enabled, the illustrated switch 644 (or any other data path control mechanism) is used to deliver the correct replacement value to the timing interpolator 604 instead of the loop filter output 638. When freezing is disabled, switch 644 moves back to pass loop filter output 638 to timing interpolator 604. In preparation for this case, replacement value calculation module 640 optionally provides re-initialization information and data 646 to loop filter 636. This has two advantages: avoiding a control signal jump when switching and continuing the interpolation and adaptation process with the replacement value as a baseline.

Instead of hard switching, (optionally) other embodiments may use soft switching (see above). This means providing and calculating some intermediate values for a smooth transition between the replacement value 642 and the new loop filter value 638.

Other embodiments may have a proposed scheme (=calculate replacement value and switch between replacement value and loop filter value) located within the loop filter module applied to modules internal signals/variables/values. Be careful.

The approach of calculating the replacement value may be to perform massive averaging on loop filter values. However, this can increase memory cost and complexity. Instead, some embodiments (optionally) utilize knowledge about the averaging characteristics and low pass of the loop filter. Thus, successive output samples 368 of loop filter 363 are expected to be correlated. Other loop filter configurations and optimizations are possible with reference to [7] and [8] depending on convergence rate requirements, supported carrier frequency offset range, supported timing offset range, and target SNR range. All of this affects the correlation characteristics of the loop filter output signal. Furthermore, it is also the TED scheme used and the current data signal characteristics, for example the roll-off of the transmit-side pulse-shaping filter and It relies on the roll-off of the receiver-side matched filter. Thus, the innovative replacement value calculator 640 can selectively perform one or more of the following functions:

Averaging over snapshots of loop filter signal 638, where the snapshot distance can be selectively configured according to signal characteristics (eg, the level of included noise represented by SNR) and different timing loop modules

→ The maximum averaging gain for a given averaging depth/filter length can be achieved.

ㆍLinear averaging is preferred over other methods (eg IIR) but not required

→ The maximum averaging gain is achieved due to the same weighting of all values.

In the case of a timing loop configuration, investigations show that a snapshot distance of 1000 results in an averaging gain equal to the averaging for all values. Thus, the memory requirement is reduced to 1000, for example, from 500,000 values to averaging over 500 values. Although TED 632 and loop filter 636 are statically configured, the noise levels in the received signal and the different roll-offs used in the matching filter justify scaling the snapshot distance up to 20 times (optional). . In some cases, the snapshot distance has a given minimum illumination time (worst case) and cannot be arbitrarily upscaled. Assuming that the timing offset remains constant, snapshots can be averaged over more than one light, or sufficient statistics can be obtained during each light.

In order to achieve the optimal snapshot distance, offline optimization can be performed (for example) for different configurations and scenarios and table look ups of the receiver can be stored. Or, for example, online optimization may be performed by analyzing the loop filter signal by correlation. Of course, the first approach represents a desirable low complexity solution. Other solutions are also possible.

The final goal of the overall optimization is that the timing offset accumulated after the illumination absence duration is only a fraction of the symbol duration, eg 0.1. Because of the pre-learning timing interpolator based on the replacement value, inaccuracies are integrated over time. This is to limit signal distortion to other modules until the timing loop is successfully unfrozen and resynchronized on the track.

Innovative Aspect 2: Freeze control driven by a power level analyzer (can be used independently or in combination with Aspect 1)

Here, a method of performing determination of a received signal according to examples will be described. Controller 650 can be used, for example, to determine the reception of a signal (eg, signal 602).

As described above, the need arises to distinguish the following.

-Signal directed to a specific coverage area where the receiver is located

-Signals directed to different coverage areas

If the other coverage area is close to the coverage area where the receiver is located, then there is a possibility that the beam (intended to be transmitted to a different coverage area, according to BSTP) is detected and incorrectly assumed as part of the signal 602 to be decoded .

The controller unit can be used with reference to FIG. 2A to distinguish between higher illumination at the power level P2 of the beam C and lower illumination at the power P1 of the beam D.

The controller unit may include, for example, a freezing controller 650 that cooperates and/or downstream with the power detector 654. The power detector 654 can, for example, check whether the power of the signal is within a certain interval. For example, the power detector 654 can also determine a specific power interval to be used next (see below). In particular, for example, at least some functions of the controller 650 can be performed by the power detector 654 or vice versa. For example, the power detector 654 can be integrated into the controller 650. Hereinafter, the term “controller units 650 and 654” may be used to indicate at least one of a power detector 654 and a controller 650.

In particular, controller units 650 and 654 activate the replacement values discussed above (eg, identified by control signal line 652, which commands selector 644). Or you can disable it. The controller units 650 and 654 can determine whether the input signal 602 is a transmission to be received or not based on other amounts or power information related to power. In some cases, other conditions besides the amount of power information or power related may also be considered. However, the operations of units 650 and 654 can also be used for different or independent purposes. (With instructions 652', 652”, 652”', the controller unit may freeze, for example, loop filter 636, AGC 612, and TED 632.)

In examples, the controller unit 650, 654 is the amount 656 derived from the power (eg, a low-pass-filtered version of the power level information), or the received signal 602 ) Can be configured to perform a determination as to whether or not power lies within a limited interval and recognize the transmission 602 to be received based on the determination. Based on the determination, the controller units 650, 654 can control the activation/deactivation of the switch 644.

In examples, the controller unit 650, 654 can detect the different lighting power levels and the qualification of other lighting(s) that will be in the appropriate power level range to be exploitable by the receiver to improve synchronization. Based on it, it supports a special activation mode "exploit other illumination". In addition, side information, such as coverage ID decoded from the received signal, can be considered for credentials. This particular activation mode can control the module differently compared to the activation mode according to the prior art. For example, the scaling adaptation of AGC 612 may be frozen or intentionally biased by a power difference, but feedback path 630 will be activated.

In examples, the controller units 650, 654 are:

The input signal 602 is a selector to activate the feedback mode (whereby the timing interpolator 604 is supplied with sample timing information 638 based on the timing error information 634 of the current samples of the signal) ( 644) is recognized that it is a transmission to be received to switch (thus confirming that a predetermined requirement, such as the current lighting has been achieved), and/or

-The input signal 602 is an unreceived transmission to switch the selector 644 to activate the replacement value providing mode (thus the timing interpolator 604 is supplied with replacement sample timing information 642) Recognizing a point (thus ensuring that predetermined requirements, such as current lighting, have not been met).

In the case of at least one of the above cases, the intermediate mode can also be triggered by the controller units 650 and 654 as described above.

The controller units 650, 654 signal the signal 602 when the controller units 650, 654 determine that the power level is within a certain interval (eg, this operation may be performed by the power detector 654). It can be understood that the signal is received and decoded. Referring to FIG. 7B, the interval 702 may be bounded by a lower interval boundary value 704 and an upper interval boundary value. This can for example constitute an identification of "power level" or "power range". Thus, the controller units 650, 654 may receive the signal at a predetermined power level (eg, power niveau) [eg, among two or more power levels to be distinguished—the at least two or more powers Levels or nives can identify whether they indicate different signal content, different beams, may be associated with different receivers. For example, in FIG. 7B, sample 708 is within power range 702 and sample 710 is outside power range 702.

The controller units 650, 654 have, for example, the power of the received signal 602 (and/or the amount derived from the received signal, eg, a low-pass-filtered version of the power level information). You can further determine how long you are within the limited interval. Thus, the controller units 650 and 654 can determine the length of time of the interval. Thus, the controller units 650, 654 may perform a predetermined search while the received signal 602 includes a power level (eg, by counting the number of consecutive samples at the same power level and/or a predetermined search time period). by analyzing the time distance between samples within a time period) the length of at least one limited time period (e.g., the length of a signal burst or the length of illumination in a certain spatial region) (712)).

In examples, the limited interval 702 can be fixed and its upper and lower interval values 704 and 706 can be fixed and predetermined (eg, defined offline).

In other examples, the limited intervals (and values 704, 706) can be defined dynamically. For example, at least one power level can be dynamically defined based on a determination that a predetermined number of (eg, at least two) consecutive power samples are within a limited interval associated with a particular power level. The controller units 650 and 654 can determine the amount derived from the received signal, or the time the power of the received signal 602 lies within the limited interval. Accordingly, the time length 712 of at least one limited time period in which the received signal 602 includes a specific power level (eg, 702) [eg, the length of the signal burst, or the receivers 110-114 It is possible to recognize the length of illumination of a specific spatial area (coverage area 104-108) where) is located. For example, the time length of the power level 702 by counting the number of consecutive samples at the same power level and/or by analyzing the time distance between samples within a predetermined search time period. 712 can be recognized. In examples, the power level 702 can be dynamically defined based on the determination that at least two consecutive power samples are within a limited interval associated with a particular power level.

In examples, the controller unit 650, 654 can check whether the recognized length of the limited period 712 in which the received signal includes the power level 702 satisfies a predetermined condition. For example, the predetermined condition is, "Is the recognized length of the limited time period (while the received signal includes the power level) at least roughly a multiple of the scheduling granularity?" Or "Are the recognized lengths of the limited time periods (while the received signal includes a power level), do you comply with the time schedule of a given transmission among a plurality of different transmissions? Checking at least one condition ( With "yes"), it is possible to support the recognition that the input signal 602 is related to the transmission to be received. Evaluating more than one criterion leads to recognition of the wrong decision. By checking ("No"), it is possible to recognize the wrong decision of the signal, thus improving the error detection capability.

The number of power levels that can be determined by the controller units 650, 654 (and in the example, by the power detector 654) can be at least two (in FIG. 2A, for example, three power levels P1, P2) , P0 is recognized, 4 power levels P1, P2, P3, P0 in FIG. 2B are recognized). (For simplicity, FIGS. 2A and 2B do not show the upper and lower spacing values indicated by 704 and 706 in FIG. 7B.) Thus, it is possible to distinguish different power levels. In particular, in some cases, at least one of the power levels may be a noise power level (eg, P0), while the highest power level (eg, P2 in FIG. 2A and P3 in FIG. 2B) Higher) may be understood to be related to the transmission intended to be received and decrypted by the receiver. Other power levels may be power levels associated with beams intended for different receivers and may also be considered noise or secondary power levels (see below).

Thus, processing 600 can suppress decoding of the input signal 602 when the latter is associated with a noise power level. For example, the controller units 650 and 654 can send a notification 660 that the signal coming into the data processor 620 is not decrypted. Additionally or alternatively, the controller unit 650, 654 activates the sieve sample timing provider 640 (e.g., via commands 652 and selector 644), such that the latter is replaced Start providing sample timing information 640 to the timing interpolator 604.

In examples, the controller units 650 and 654 can track the duration at which different power levels exist to derive scheduling information. For example, the controller units 650 and 654 can be configured to recognize that within a predetermined search time period, a plurality of samples are within a certain power range to recognize a particular power level. This technique can, for example, allow a receiver to learn the scheduling without needing to explicitly signal the scheduling information from a transmitter (eg, satellite 120), and can be performed in a specific initialization session. .

In examples, initialization is performed to obtain parameters related to at least one or a combination of power to determine at least one power level to be used next to recognize transmission, time information, and/or quality information to be received. The controller unit (650, 654) is an amount of power derived from the power over the period of the received signal, or time progress of power to receive the signaled information (signalled information) to perform the initialization or to perform the initialization ( temporal evolution).

In examples where a transmitter (e.g., satellite 102) also signals a scheduling plan (e.g., BSTP), to verify the correctness of the received transmission and/or to verify the accuracy of scheduling information The duration of the time period for receiving a hazard can nevertheless be checked by the controller units 650, 654. Here, the controller units 650 and 654 check whether the current power level lies in a limited interval and interval boundaries determined based on the previously derived power level scheduling information.

The controller units 650, 654 can store time information characterizing (and/or describing) time portions of different levels of the received signal 602, an amount derived from power, or the received Information about the power levels of the signal can be stored. The controller unit 650, 654 can also be configured to recognize time periods associated with a transmission to be received, at the next moments, based on at least stored time information (eg, scheduling).

The controller unit 650, 654 (eg, to set the interval boundaries 704, 706) may receive the received signal during different time portions for recognition of power levels and time periods associated with the transmission to be received. Stored information about power levels can be used.

In examples, processing 600 (and the receiver also) may be in at least one of two modes:

Reduced-power-consumption mode (eg, 699) based on derived scheduling information (eg, based on derived scheduling information, at periods of time it is estimated that there is no transmission to be received by the receiver) about],

Normal reception mode (eg, 698) when a transmission to be received is expected based on the derived scheduling information.

In reduced power consumption mode 699, processing 600 may be in a replacement sample timing providing mode (thus timing interpolator 604 is replaced while loop filter 636 and/or TED 632 is deactivated) Sample timing information 642 is supplied). Also, in the reduced power consumption mode 699, the received signal 602 may not be decoded. In the normal receive mode 695, the process 600 may be in a feedback mode (the timing interpolator 604 is supplied with sample timing information 638, and/or the loop filter 636 and/or TED) (632) is activated, and/or replacement sample value provider 640 does not provide replacement sample timing information 642 even if it can continue to perform averaging). Also, in the normal mode, the input signal 602 can actually be decoded.

The controller units 650 and 654 can recognize periods in which different power levels exist and rank different periods of time to recognize the periods of time for transmission to be received. For example, the controller units 650, 654 can determine during which period the highest power level was, the second highest power level, and the like. For example, the period in which the highest power level is present can be selected as the illumination period. Low power levels can be associated with noise. The remaining power levels can be considered secondary power levels. Thus, the lowest measured power level (eg, P0 in FIGS. 2A and 2B) may be interpreted as noise, but the remaining non-highest-ranked power levels (eg, P1 in FIG. 2A and P1 and P2 in FIG. 2B) may be interpreted as secondary power levels. The secondary power levels are for possible hand-over (eg, when it is no longer possible to acquire a signal at the highest power level) and/or to identify a suitable beam for hand-over. It can be used to track power level differences over time. Hand-over is needed when the receiver moves and goes from one coverage area to the next coverage area (eg, it moves from area 104 to area 106). In this case, the user data is no longer provided by the beam of one coverage area, but by the beam of the next coverage area. This observation and tracking of power levels and/or power level differences also allows determining whether a signal of the secondary power level can be used to improve receiver synchronization. For example, if the secondary power level is very close to the main power level (ie, higher than a given threshold), good signal quality can be expected from the signal of the secondary power level. Therefore, it can improve synchronization performance/accuracy/stability.

7C shows an example of a method 720 that may be performed by controller units 650 and 654. In step 722, the power levels of the input signals and their time length are determined. Referring to FIG. 2A, the controller unit 650, 654 describes time periods related to power levels and knowledge of the power level (eg, P0, P1, and P2, respectively, by their boundaries 704, 706) In order to describe). The retrieved (retrieved) power levels are ranked from the highest power level (eg, P2 in FIG. 2A) to the lower power level (eg, P0). In step 724, the power level with the highest power (eg, the highest power level such as P2 in FIG. 2A) is determined (eg, determining the time period with the highest rank). Referring to FIG. 2A, the controller units 650 and 654 can thus determine that the illuminated period matches the length of the interval associated with the power level P2 (highest rank), and thus super-frames SF7 and SF8 Can be understood as the illuminated period. Similarly, the controller unit 650, 654 can understand other time periods (eg, super-frames SF1-SF6 and super-frames SF9-SF12) as noise periods. In particular, the periods associated with super-frames SF9 and SF10 will be understood as the period during which the beam directed to different coverage areas generates unintended illumination, which is considered noise. In step 726, the period of illumination with the highest power level (eg, P2) is selected as the correct illumination period. Thus, for the next super-frames, the input signal 602 will only be decoded when it is in the correct illumination period (eg, super-frames SF9 and SF10).

FIG. 7D shows possible results of the method 720 applied to the scenario of FIG. 2A. The table 750 may be obtained and stored in the memory unit. Each row can be associated with a different interval (P0, P1 and P2). The column 752 is related to a specific time period, each related to the power intervals P0, P1 and P2, respectively. In this case, column 752 has two sub-columns, a starting sub-column 752a representing the frame at which the period begins and an ending sub-column 752b representing the frame at which the period ends. ). Column 754 may indicate the retrieved power levels (P0, P1 and P2). In this case, column 754 has two sub-columns, i.e., a high power boundary sub-column at which the period starts (754b) and a power interval (e.g., 704 in FIG. 7B). The lower power boundary sub-column 754a, which indicates the lower boundary (e.g., P_x-ε_1), and the upper limit of the power interval (e.g., 706 in FIG. 7B) For example, it is subdivided into an ending sub-column 752b representing P_x + ε_2). Column 756 represents the rating of a particular power level. It is assumed that the noise is P0 as a low-rank-interval. The illumination period is selected as super-frames (SF7-SF8) (power level P2) as the highest-rank-interval. The secondary power level is P1.

Processing 600 is within received signal 602 to determine the start (eg, 120a, 122a, 124a) and/or end (eg, 120b, 122b, 124b) of the period of transmission to be received. The encoded at least one piece of information (eg, a sequence and/or preamble and/or a specific bitstream) may be decoded and/or detected. In some examples, both power level and decoding can be used, and transmissions to be received when characteristic information is decoded and/or detected can be already recognized even if the power is still not within a limited interval.

Processing 600 may include upper and lower boundary boundary values and/or time and/or time information associated with at least one power level [eg, range] [eg, scheduling related and/or BTSP related information and/or Or modifying], it may receive signaling transmissions from a transmitter (eg, satellite 102). The controller unit 650, 654 can acquire signaling transmissions, whereby the controller unit 650, 654 can at least partially be controlled by the signaling transmissions or obtain side-information.

In some examples, a redundancy strategy can be used to verify the correctness of the determination of the power level. For example:

-Perform a determination of whether the power of the received signal 602 is within the interval 702; And

It is possible to confirm the correctness of the decision based on at least one of the following strategies:

o Detecting a slope in power that is above or below a predetermined threshold. For example:

■ If the positive increment in the detected power of the received signal over time is greater than the upper threshold, a fast increase in the detected power is determined, and/or

■ If the negative increment in the detected power of the received signal over time is lower than the negative lower threshold, a fast decrease in the detected power is determined; And/or

o using time information obtained with previous power level decisions [eg, to predict the time at which the transmission to be received is expected to start using time extrapolation]; And/or

o decoding [or detecting] specific information encoded in the received signal (eg, sequence and/or preamble and/or specific bit stream); And/or

o detecting quality information [eg, signal to noise ratio] or inferring it from other modules (eg, signal to noise ratio estimator); And/or

o Using commands and/or signaled data from the transmitter.

For example, the rapid increase or rapid decrease in the detected power may be related to the fact that the received signal 602 is now at a different power level (this is the signal actually received in the case of a fast positive increase). In the case of information and fast reduction, it may lead to information that the signal is no longer received). Additionally or alternatively, the power level can be validated using one of the other strategies listed above.

In examples, the controller units 650 and 654 can dynamically determine the value of the power level (eg, the method 720 can be performed in real time). For example, the power level can be considered to be determined dynamically when a certain number (eg, 2) of consecutive power samples (eg, 706, 708) are recognized as being within a certain range. .

The controller units 650, 654, for example,

-As a first condition, the current power sample extends up and down from the interval determined by the first preceding sample of the power of the received signal (e.g., the first preceding sample value) Within the intervals], and

-As a second condition, it can also be configured to determine whether the current sample is also within an interval determined by the positive, derived from the power, or a second preceding sample of the power of the received signal.

Continuity of power levels when both the first and second conditions are achieved.

Referring to FIG. 7, a method for determining power interval 732 and time length 730 is now discussed. Since pACT [i] is within the interval defined by the previous power sample pACT [i-1], power sample pACT [i] confirms the first condition. Facts, conditions

Is identified where pmargin represents the margin. Also, pACT [i]

The second condition as is confirmed.

Thus, the power interval 730 is identified. For the next power sample pACT [i + 1], the same two conditions with respect to pACT [i] and pACT [i-1] are also confirmed. Thus, pACT [i + 1] is at the same time interval of pACT [i]. The same applies to the subsequent power sample pACT [i + 2] and the like. At a certain time instant pACT [i + N], the above conditions are no longer achieved. Therefore, it is understood that the time length 730 of the interval is N + 2. In particular, in the instantaneous pACT [i + N + 2], the power interval 734 is identified.

Therefore, the condition

Can be used to check if a new interval is found and to recursively obtain the time length of the interval.

에서, 최저 값은 하한(lower boundary) (704)으로 이해될 수 있고, 테이블 (750)의 컬럼 (754a)에 저장될 수 있다. 최고 값은 상한 (706)의 최고 값으로 이해될 수 있고, 테이블 (750)의 컬럼 (754b)에 저장될 수 있다. p_act [i-2] 값은 P0, P1 또는 P2로 이해될 수 있다.In particular, spacing

In, the lowest value can be understood as the lower boundary 704 and stored in column 754a of table 750. The highest value can be understood as the highest value of the upper limit 706 and can be stored in the column 754b of the table 750. The p_act [i-2] value can be understood as P0, P1 or P2.

The controller units (650, 654) are:

Configured to tolerate a predetermined number of consecutive power samples that do not satisfy the first condition and/or the second condition without recognizing the end of the power level,

-Configured to recognize the end of the power level when a greater number of consecutive power samples than a predetermined one do not satisfy the first condition or the second condition.

Referring to FIG. 7A, the controller unit 650, 654 determines whether the current sample of the power of the received signal is outside the tolerance interval 742 (described by “additional thresholds” in FIG. 7A). You can decide whether or not. The allowable interval 742 is greater than the interval 744 determined by a sample immediately preceding the power of the received signal (eg, p_act [i-1] ± p_margin above). Sample 746 is outside the allowable interval 742 of sample 749, while sample 748 is within tolerance interval 742 (outside interval 744 of sample 749). The controller units 650 and 654 may be configured to recognize [eg, immediately] the end of the power level in the sample 746 when the sample of power of the received signal is outside the allowable interval 742 for the first time. Moreover, the sample 748 is allowed to lie outside (at least once) the gap 744 determined by the immediately preceding sample 749. In this case, the end of the power level is not recognized.

In examples, the controller units 650, 654 are:

-Can operate according to the first and second operation modes (eg, the second mode is initiated in response to the end of the first mode), and in at least one of the first and second modes, the controller It is configured to perform a combination of at least two of the techniques or at least one of the following techniques:

o a technique for determining if the power of the received signal lies within a limited interval;

o A technique to check if power is determined at an expected time period (eg, as extrapolated from previous measurements);

o technology for decoding or detecting specific information (eg, sequence and/or preamble and/or specific bit stream) encoded in the signal to be received;

o technology for checking quality information (eg signal to noise ratio);

o Technology for checking the satisfaction of the criteria according to information signaled from the transmitter;

o A technique for detecting whether the slope in the power is above or below a predetermined threshold (eg, the detected increase in power of the received signal over time is the lower limit) ) By determining that it is greater than an upper threshold indicating a rapid increase and/or a negative increment in the detected power of the received signal with respect to time, resulting in a rapid decrease in the detected power. By determining that it is lower than the negative lower threshold indicated].

In the first mode, the controller unit 650, 654 can determine if the sample power lies within a limited interval (eg, based on power measurements) without considering the encoded signal in the signal. have. In the second mode, the controller units 650, 654 (eg, initiated in response to the end of the first mode):

Determine if the power sample is within a limited interval (eg, based on power measurements); And

It verifies the accuracy of the decision based on whether the encoded information in the received signal is compliant with the recognition of the transmission to be received based on the power.

In the above examples, power (for example, a value such as pact [i]) is mentioned. However, the power values may, in some instances, be replaced with positive values associated with the power, such as an infinite impulse response (IRR) filtered version of the power.

In some examples, the techniques of the second aspect can be independent of the techniques of the first aspect. For example, the controller units 650, 654 can be used without a replacement timing provider 640. FIG. 6D shows an example of a process 600 ′ where replacement timing information 642 is not provided when no-illumination is detected. In that case, the final sample timing information 638 provided by the loop filter 636 can be frozen.

Discussion of the techniques described above is carried out here.

In one embodiment, the controller units 650 and 654 rely only on the feedback of the analyzer 656 and power level detector. This is a robust configuration because it is non-data aided and not sensitive to synchronization offsets in terms of timing or frequency. Thus, it is a fallback solution and a baseline when other more precise methods fail. For example, the power level detector and analyzer track and provide all information regarding different detected power levels as well as notification of power level termination or start.

In other embodiments, the freeze control (optionally) evaluates data exchanged with the block “further data processing” as shown in FIG. 6. For example, a preamble/known sequence detection algorithm provides information about detection events. Since the preamble will be included in the signal at the beginning of each light at least, it may help to send a freezing off signal earlier than waiting for the power level detection signal, which may result in a slight decision delay. Can have

The preamble detection can be (optionally) used as a confirmation of "end of low power level" information from power level detection or in combination.

On the other hand, the freeze control can also pass its freeze signals to the block "additional data processing" 620, where modules need it to cope with bursty input data. Can be. This case may occur during acquisition when the terminal is switched on:

For example, initially the freeze control may rely solely on the power detection until, for example, timing and frequency offsets are sufficiently compensated. The freeze signal can also (optionally) be provided to the preamble detection algorithm of the block “additional data processing”, whereby it can adapt its preamble detection threshold. When the detector threshold converges, the preamble detection events can be selectively fed back to the freeze signal.

In further embodiments, information signaled through a satellite signal regarding beam-ID/coverage-ID/BSTP status and update, and/or information on the measured SNR is also received from the block “Additional data processing”. It can be passed to other modules, such as calculating replacement values for reconstruction. In addition, the freeze control may use it for sleep mode signaling and/or freeze prediction for other modules during the absence of lighting and to identify the recurring nature of the BSTP. For this reason, you can keep this data in a history table.

As mentioned above, the power level detector and analyzer is a baseline algorithm that supplies freeze control. As illustrated in FIG. 6, the received signal may be used before AGC. This makes sense because the AGC does not confuse the power level detector and analyzer when the signal is up or down scaled according to the control target. For very slow AGC adaptation or other means for compensating for the AGC power scaling effect, the power level analyzer can be deployed even after the AGC. Also, it can be optionally placed behind a matching filter to limit the noise power entering the power level detector. Since the AGC calculates and averages the power of the received signal anyway, a power level analyzer can optionally be placed in the AGC to save resources.

The two approaches discussed above search for directly identifying the start and end of lighting (detection of rising/falling edges), while the approach of the present invention searches for power levels. Depending on the configurable snapshot distance, these snapshots are compared to see if successive snapshots are within a configurable margin. As shown in Figure 7, it is effective to analyze the averages IIR1 and IIR2. The end of the power level can be identified immediately, while the short history of the snapshots (e.g., not necessarily, at least two) can assist in power level detection, whereas the start of power level determination is used. It may be delayed depending on the history length. For the example of Figure 7, the history of two snapshots is considered and compared to the actual snapshot. It should be noted that if one (or more) snapshot(s) accidentally deviates from the margin, a longer history will be error tolerant.

More specifically, snapshots from the smoothed power envelope of the two IIR filters are considered, i.e., the actual snapshot p_act [i] = p_IIR1 [k = iΔk] or p_IIR2 [k = iΔk], and Δk is two snaps This is a configurable time interval between shots. Identifying certain power levels (within some margin) and the duration of these power levels works as follows.

ㆍSnapshot Counter i

-For example, the snapshots p_act [i] are analyzed in relation to certain power levels taking into account the sliding history of two snapshots. Evaluate the interval check criteria for each i

o If the criteria are met, mark these three indices as "Power Level Discovery".

If this is the first time, set the exponents to i_first=i.

o If the equation is no longer maintained = “power level end”

Then i_last=i

• At the end of each power level, save the data in a list:

o Average for N detected power levels:

o Calculate the power level duration from i_first and i_last.

ㆍList analyzer

o Check and calculate the duration of the power level in relation to multiple super-frames

의 잘못 분리된 파워 레벨들이 식별되고 재-결합(re-combined)될 수 있다.→ For example, at the same level

The incorrectly separated power levels of can be identified and re-combined.

o Perform pattern analysis to identify the BSTP period and the number of detected lights/beams

o Potential collection of additional information available from other modules such as SNR and Coverage-ID for each light

o A consistency check such as one coverage-ID per power level can also be performed.

For the results of Figure 7, a relative margin for power level detection of 2% can be used.

→ That is, when x = 1, 2, the margin is p_margin [x]=p_act [i-x]2%.

With pure detection of power levels and optional expansion to their start and end, the power level analyzer stores identified power levels (representative snapshot values or average power of snapshots) and performs sanity checks. For example, the length of the power level is compared to the granularity of the lighting duration. For example, the analyzer can also identify power level patterns and recurring power levels. With this information, the freeze control can selectively cross-check BSTP information. Furthermore, this identification signals the start and end of the power level as well as the events of the end of the light (power dropping after the high power level is confirmed) and/or the start of the light (power rising after the low power level is confirmed). It can be optionally used to confirm. Thus, thus, different power levels of different beams can be distinguished and tracked, as shown in FIG. 2A.

Of course, this approach can be combined with the threshold-based detectors mentioned above. For example, the end event of the power level can be mutually checked against thresholds, for example, the thresholds can be calculated from other snapshot power values or maximum/minimum powers stored in the analyzer. The power level detector and analyzer can also optionally be used with a slope-based detector to confirm the detections. Note that the possible power detection delay (between the detection of the rising edge and the real rising edge of power) is not critical because of the very precise timing extrapolation by the replacement value. As noted above, the freezing ON/OFF trigger can also optionally be associated with known sequence detection feedback as soon as possible.

A further optional extension of the power level detector and analyzer employs different threshold/interval comparisons to enhance the aforementioned decision delay due to averaging. It detects “leaving/end of a power level”. The “actual power value is significantly away from recently tracked power level” event is interpreted as “start of new power level”, often negative It is called a negative indication. The pure interpretation of “power level exit/end” to “beginning of a new power level” based only on the power level detector without an additional threshold checks whether there is a largely changing power going on without providing a reliable decision. do.

And to determine what is important, an additional threshold/interval is used (relative to previous power values or recent power level). This threshold/interval is of course greater than the margin used in the power level detector. This approach, reflecting the decision delay enhancement, is shown in the figure below. As can be seen in the figure, the cases of “rising power” and “falling power” can be distinguished according to which threshold is reached.

6C shows an example of the controller units 650, 654. The power detector 654 can, for example, receive input from a matching filter 608 to obtain a version 610 of the input signal 602 (different versions of the input signals are different examples, such as a matching filter ( 606) can be used in signals taken before). The power detector 654 is a power sample measurer that can obtain a sample 6602 (eg, pact [i]) associated with the current sample of the version 610 of the signal 602, for example ( 6540). The power sample meter 6540 can additionally or alternatively provide a filtered or averaged version of the power. The power sample meter 6540 can include a sample counter 6544, which can provide a current index 6462 of the current sample of version 610 of signal 602. The sample counter 6544 can, for example, count how many consecutive power samples are in the interval 744 and/or how many samples 748 are outside the current interval 744. The power detector 654 can include a power level definer that determines the current power level from the current index 6462 and samples 6252. The power level definer 6548 can thus provide power information 656 to be provided to the freezing controller 650. Freezing controller 650 may include a scheduler 6650 that can obtain scheduling information 6562 from power information 656. (Scheduler 6450 may also obtain information from other components, such as signaling, in some examples) Switch controller 6504 can obtain scheduling information 6562 and power information 656. In some examples, switch controller 6504 can check whether the current power level conforms to scheduling information 6552. Based on the power information 656 or the scheduling information, the switch controller 6504 can determine whether the receiver is currently illuminated (and/or whether it achieves the predetermined condition). Based on the power information 656 and/or the scheduling information, the switch controller 6504 provides the feedback signal 638 to the timing interpolator 604 and the replacement sample timing information 642 to the timing interpolator 604. Switch 644 can be operated to perform a selection between the provisions of the.

Innovative Aspect 3: Framing Verification and Correction to Tackle Sporadic Symbol Offsets

The signal processing 600 of the receiver (eg, 110, 112, 114) may include a further data processing block 620 detailed in FIG. 8. The timing loop components of processing 600 can be understood to be included in block 680 with reference to FIG. 6 (or “burst-mode capable timing loop”).

Now is an example of how frames can be recognized from sequences of symbols.

Data 618 is provided, for example, from block 680 to block 620 in the form of consecutive symbols. Block 620 may include, for example, preamble detector 802 and/or framing verification and correction block 808 (framing verification and correction). Blocks 802 and 808 can form data processor 820 that identifies the start and end of frames in frame sequences. Block 802 can provide symbols to block 808 in symbols in ordered sequences 804, which may be, for example, frame candidates. Block 802 (which may be a preamble detector) is for example specific sequences (eg, according to certain standards, protocols, etc.) that are assumed to be uniquely located in fixed fields of frames (eg For example, it may perform known strategies such as recognizing the preamble of the header of the frame. Additionally or alternatively, block 802 can compare the time instant at which a new frame is expected.

The data field within a frame or the start of each frame may be signaled by block 802 using, for example, signal 806. The signal 806 may be binary signaling information flags (framing data flag) that can be synchronized to the symbols. Each flag/bit can indicate a different field. For example, the flag may be 1 when pilot symbols are present (eg, when a pilot sequence is determined), while the flag may be without a pilot symbol (eg, a pilot sequence may be used). When it is no longer determined, it may be 0, for example, if a payload is present. At the start-of-frame, the flag can thus be 1 and remain 1 for all initial symbols of the frame, while the flag can be returned to 0 when the pilot sequence ends. have.

An example is provided by FIG. 10. Here, the sequence of symbols S0, S1,... , SM, S (M + 1), S (M + 2)… Are sequentially obtained by block 808 from block 802. Block 802 recognizes the start of the frame in symbol S1 (eg, by analyzing the preamble or by the fact that the first symbol is related to the expected time instant). Thus, block 808 is:

-Sequence S1… A first frame candidate 1000 (and associated signal 806) consisting of SM,

-Sequence S0… A second frame candidate 1002 (which is signaled via signal 806 and shifted for one symbol prior to the first symbol of the first frame candidate 1000), consisting of S (M-1),

-Sequence S2… Evaluate another second frame candidate 1004 consisting of S (M+1) (and signaled via signal 806 and shifted for one symbol after the first symbol of the first frame candidate 1000) Can be.

Block 808 can evaluate the characteristics of the signal 804 for the frame candidates 1000-1004 to identify the correct start of the frame among the candidates. Block 808 can perform hypothesis testing.

For example, block 808 can perform correlation processes on signal 804 with respect to candidates to recognize what is most suitable.

For example, block 808 uses cross-correlation processes between each frame candidate and a known sequence of symbols (eg, expected preamble) to identify the correct frame based on cross correlation processes. It can be done. Using the correlation process, it is possible to understand which frame candidate is the highest probability correct frame.

In examples, block 808 demodulates the frame header of the first and second frame candidates, a re-encoded and/or re-modulated sequence of symbols to identify the correct frame based on the cross-correlation processes. And/or decode, and perform the cross-correlation processes between the re-encoded and/or re-modulated version of the frame candidate frame header and each frame candidate frame header. This is particularly relevant if there are no known sequences available for verification. In general, frame header decoding is much less complex than frame data decoding (using much longer code words).

In some examples, for example, amplitude and/or phase (eg, complex phase) can be compared to expected amplitude and/or phase. If the candidate has no correct phase or correct amplitude (or amplitude or phase within a predetermined range), the frame candidate can be discarded. Thus, frame candidates with a phase and/or amplitude that most closely resemble the expected phase and/or amplitude can be identified as correct.

If one of the second frame candidates 1002 and 1004 is identified as a correct frame, the framing signaling 806 is shifted to be in the correct position corresponding to the expected time instant. The updated and confirmed signaling then appears as (correct framing data flag) 812.

With respect to how cross-correlation processes are performed, FIG. 9 shows some demonstrating strategies that can verify the identified correct frame.

For example, comparisons can be performed at cross-correlation amplitudes to verify the correct frame.

Examples of verification are provided in FIG. 9 with reference to the examples in FIG. 10. The obtained cross-correlation values are provided in abscissa. In FIG. 9A, the detected start of the frame is the first of the second frame candidates 1002 (this is shifted one symbol before, ie, "-1"). In FIG. 9B, the detected start of the frame is the first frame candidate 1000 (as accurately represented by block 802). In FIG. 9C, the start of the detected frame is a frame candidate 1004 (after one symbol, ie shifted to "+1"). In the three cases, the correct frame shift is verified because the correct frame is the only frame with a cross-correlation value greater than the threshold 902, while the incorrect candidate has a cross-correlation below the threshold 902 ( validated). If the correct candidate is verified, the frame can be decoded.

9D shows an error state in which the cross-correlation values of all candidates are within a range defined by a smaller predetermined threshold 904 and a larger predetermined threshold 906. In this case, an error notification is transmitted because the correct frame cannot be identified.

9E shows an intermediate timing synchronization with two candidates 1002, 1000 having a greater cross-correlation than a larger predetermined threshold 910 (eg, may be the same as the threshold 906 or 902). state), but one candidate 1004 has a smaller cross-correlation than a predetermined threshold 908 (eg, may be the same as threshold 904).

The verified frame 810 (with the verified and corrected frame signaling 812) can be provided to an additional data processing module 814 that can use the information contained in the received (and decoded) data.

In some examples, verification of correct frame alignment with respect to signaling 806 will trigger the transmission of notification 840 (which can be understood as communication 660 or part thereof) to the freezing controller 650. It can thus use this information for the purpose of controlling other components of processing 600. In particular, the freezing controller 650 can use the notification 840 660 to confirm the power level 656 as detected by the power detector 654. Based on the notification 840 (660) and/or the detected power 656, the freezing controller 650 may also switch between a feedback mode and a replacement value providing mode (and/or an intermediate mode).

In particular, however, block 620 may also be deactivated by command 842 (660), which may also be sent by freezing controller 650, for example, when a non-illuminated state is identified. Accordingly, block 620 will not decrypt useless data when controller units 650 and 654 determine the receiver's non-illumination (eg, 110-114).

A discussion of the third innovative aspect is now provided.

The additional module “frame checking and correcting” 808 shown in FIG. 808 is located immediately after the preamble sequence detection 802. It receives data symbols 804 as well as corresponding framing information 806 generated in the preamble detector 802. Since this information may be inaccurate, as already described, module "frame verification and correction" 808 checks framing information 806.

The different types of framing check methods are:

ㆍDetection of another data sequence (known to the receiver) after the preamble sequence (once or repeatedly):

For example, cross-correlation can be applied. Here, a low complexity implementation can be achieved by taking advantage of the fact that other data sequences are expected to appear only in the range of +/- 1 symbols around the nominally predicted time instant signaled by the framing information. In this case, three correlation results are compared in amplitude. The symbol offset detection decision is made based on the largest of the three correlation amplitudes.

ㆍCreate another data sequence to compare:

For example, by demodulation and decoding of the received code word and re-encoding and modulation of this code word at different framing hypotheses with respective symbol offsets -1, 0, +1. Then, the above-mentioned cross-correlation method is used, and each received code word hypothesis is correlated with a corresponding re-encoded and modulated code word version. Then, a symbol offset detection decision is made again based on the largest of the three correlation amplitudes.

ㆍData characteristic change detection:

For example, the amplitude or complex phase of the received signal changes in a predictable way for the detector to determine the correct time of change and compare it to frame information to determine the symbol offset.

810) 또는 프레이밍 정보의 수정 시프트 (변형806

812)에 의해 달성될 수 있다. 후자의 수정은 정보 (812)가 "올바른 프레이밍 데이터 플래그"라고 불리는 도 8에 도시되어 있다.After identifying a non-zero symbol offset, the correction inserts/deletes data symbols (variant 804

810) or a modified shift of framing information (variation 806)

812). The latter modification is shown in FIG. 8 in which information 812 is referred to as "correct framing data flag".

Of course, in addition to determining the maximum amplitude hypothesis, additional checks and analyzes can be performed. This is illustrated in FIG. 9 where different detection cases and applied thresholds are shown. The description of the following analyzes takes into account the actual hypothetical correlation amplitude, but their history can also be considered.

“Peak Validation” by testing whether the two lower correlation amplitudes are below the threshold derived from the current (and potentially also previous) maximum correlation amplitudes. Thus, three detection cases in FIGS. 9A, B and C These are proven because they are below the dash-dotted threshold line.

ㆍ “Timing Convergence Ongoing”

If there is a second correlation amplitude that is very close to the maximum correlation amplitude as shown in FIG. 9E, it reflects that the correct sampling time instant should be between two high correlation amplitudes. This means that timing synchronization is not yet settled and convergence is in progress. The first threshold is needed to identify the second high correlation amplitude, and the second threshold is needed to distinguish this case from the error case in FIG. 9D.

• “Error” All three amplitudes show very similar values within the confidence interval (ie, upper and lower thresholds). This can occur because of a symbol offset greater than that covered by the amount of hypotheses or because the signal is not present.

In addition, amplitude values that do not seem reasonable lead to “errors” such as two very high correlation amplitudes at symbol offsets +1 and -1 while the low value is at zero.

Of course, the data flow must be buffered until a decision is possible and correction can be applied.

Possible aspects (optionally available individually or in combination in embodiments of the invention):

ㆍSee timing loop concepts, [7] and [8]

o use of DA- or NDA-timing error detectors, and/or

o use of averaging of loop filters and timing error signal, and/or

o Freeze the timing loop feedback so that the interpolator continues to run according to the latest feedback value

ㆍFreezing the AGC scaling adaptation

Power detection focused on rising/falling edge detection, eg threshold-based or slope-based

ㆍAlgorithm for preamble/known sequence detection, see example [9]

Innovative aspects (can be used individually or in combination with any of the embodiments described herein):

Main aspect: When the freeze signal is set to ON, a replacement value is calculated from the loop filter output signal and/or the loop filter internal signal, and this value is applied instead of the instantaneous loop filter output. Optionally, re-initialization information is selectively prepared for loop filter re-activation. Optionally the freeze signal is OFF and the loop filter switches back on restart based on the re-initialization information.

o Optionally configurable, for example, with respect to the snapshot distance depending on the roll-off used

o Optionally use enhanced bit-width for NCO input compared to standard approach

Freezing control (sub-side, can be used with the main side, but can be used separately) can be driven by any combination of (optionally) other methods below in addition to the power level detector. “Combination” may be joint/simultaneous use or continuous use, or even both.

o Power detection that identifies power levels (baseline for delayed acquisition due to robustness) rather than correct start and end of lighting

→ optionally tracking the history of previously identified power levels to rate actual detections

→ Optionally adaptive threshold calculations and updates

→ Power detection is also used for cross-validation of optionally valid freezing ON/OFF

→ Optionally improved detection delay by applying an additional threshold/interval check to identify significant power changes to be displayed early at the start of a new power level

o Preamble/known sequence detection (in tracking mode)

→Freezing control can optionally drive the adaptive threshold calculation freeze of the preamble/known sequence detection algorithm based also on power detection information!

o Internal trigger for ON/OFF of freeze signal such as counters (3/4 of super-frame)

o External indicators/triggers for turning on/off the freezing signal

ㆍFreezing control additional optional features (one or more features can be used selectively)

o The controller can also be used to signal sleep mode to other modules of the receiver.

To this end, the lighting statistics of the history and/or signaled side information can be selectively used so as not to miss the lighting.

o Ability to distinguish and detect between bursty or continuous signal reception:

■ Busty signal reception:

Reception of one or multiple lights of one or different coverages is selectively identified by evaluating the history of detected power levels. For example, through this statistic the strongest power levels can be recognized and used to un-freeze and adapt. Signaled information such as coverage-ID or complementary information regarding peak amplitude and correlated peak detections or measured SNR can be considered for joint evaluation and fine tracking of differences. .

■ Continuous signal reception:

If the power level detection does not detect a change in power level or significantly different power levels, for example, the assumption that a continuous signal will be received first is tested. Thus, freezing is set to OFF to start the timing loop, for example, a preamble/known sequence detection algorithm is applied to confirm the hypothesis. If negative, only noise is received and no signal is received.

The above concepts where the timing loop configuration can be modified/adjusted:

o Loop filter configuration: high loop gain for faster convergence during the initial time duration; And/or

o Loop filter configuration: higher loop gain for faster convergence for higher SNR and less loop gain for lower SNR; And/or

o Timing error detector: switching calculation mode/principle, for example between NDA- and DA- modes

ㆍSupporting module to ensure correct framing synchronization

o Implementation utilizing the fact that only very few symbol offset hypotheses should be checked, e.g. 3 cases of checking symbol offsets of -1, 0, 1 with respect to the expected framing after timing loop convergence

o Rating of hypothesis decisions derived by sanity checks: “prove peak” and/or “progress timing convergence” and/or “error”

Implementation alternatives

Examples can be implemented in hardware according to specific implementation requirements. The implementation is a digital storage medium in which electronically readable control signals are stored, for example, a floppy disk, a digital versatile disc (DVD), a Blu-ray disk, a compact disk (CD), a read-only memory (ROM), Programmable Read-Only Memory (PROM), Erasable and Programmable Read-only Memory (EPROM), Electrically Erasable Programmable Read- Only Memory (EEPROM) or flash memory, and cooperate (or cooperate with) a programmable computer system to perform each method. Thus, the digital storage medium may be computer readable.

Generally, examples may be implemented as a computer program product having program instructions, and the program instructions operate to perform one of the methods when the computer program product is executed on a computer. The program instructions can be stored, for example, on a machine-readable medium.

Other examples include computer programs for performing one of the methods described herein, stored in a machine-readable carrier. In other words, an example of a method is, therefore, a computer program having program instructions for performing one of the methods described herein when the computer program is executed on a computer.

A further example of the above methods is, therefore, a data carrier medium (or digital storage medium, or computer readable medium) comprising a computer program recorded on a data carrier medium for performing one of the methods described herein. Data carrier media, digital storage media or recording media are tangible and/or non-transitionary rather than intangible and transitory signals.

Additional examples include a processing unit, eg, a computer, or a programmable logic device that performs one of the methods described herein.

Additional examples include computers with computer programs for performing one of the methods described herein.

Additional examples include devices or systems that transmit (eg, electronically or optically) a computer program for performing one of the methods described herein to a receiver. The receiver may be, for example, a computer, mobile device, memory device, or the like. The device or system may include, for example, a file server for transmitting the computer program to the receiver.

In some examples, a programmable logic device (eg, field programmable gate array) can be used to perform some or all of the functions of the methods described herein. In some examples, the field programmable gate array can cooperate with a microprocessor to perform one of the methods described herein. In general, the method can be performed by any suitable hardware device (apparatus).

The above examples may refer to radio transmission, such as radio frequency (eg, RF) transmission.

The above example is an illustration of the principles discussed above. It is understood that modifications and variations of the arrangements and details described herein will be apparent. Accordingly, it is limited by the scope of the impending claims, not by the specific details presented by the description and description of the embodiments herein.

References:

[1] J. Anzalchi, A. Couchman, C. Topping, P. Gabellini, G. Gallinaro, L. D'Agristina, P. Angeletti, N. Alagha, A. Vernucci, “Hopping in Multi-Beam Broadband Satellite Systems,” 2010 5th Advanced Satellite Multimedia Systems (ASMS) Conference and 11th Signal Processing for SPSC Space Communications) Workshop, Cagliari, 2010, pp. 248-255.

[2] X. Alberti and JM Cebrian and A. Del Bianco and Z. Katona and J. Lei and MA Vazquez-Castro and A. Zanus and L. Gilbert and N. Alagha, "System capacity optimization in time and frequency for multibeam multi-media satellite systems (optimizing the system capacity of time and frequency for multimedia satellite systems)," 2010 5th Advanced Satellite Multimedia Systems (ASMS) Conference and 11th Signal Processing for Space Communications (SPSC) Workshop, Cagliari, 2010, pp . 226-233.

[3] H. Fenech; S. Amos, Eutelsat Quantum-a Game Changer, 33rd AIAA International Communications Satellite Systems Conference (ICSSC), QT Surfers Paradise, Gold Coast QLD Australia, September 2015 7 -10 days.

[4] E. Feltrin, S. Amos, H. Fenech, E. Weller, “Quantum-Class Satellite: Beam Hopping” on the Flexible Flexible Telecom Payloads On the 3rd ESA workshop. March 2016.

[5] ETSI EN 302 307-2 V1.1.1 (2014-10), Digital Video Broadcasting (DVB); Second generation framing structure, channel coding and modulation systems (...); Part 2: DVB-S2 Extension (DVB-S2X).

[6] C. Rohde, R. Wansch, G. Mocker, S. Amos, E. Feltrin, H. Fenech, “of DVB-S2X Super-Framing for Beam-hopping Systems (DVB-S2X super for beam hopping systems Frame applied),”The 23rd Car and Broadband Communication Conference, October 2017, Esthe, Italy.

[7] Mengali, D'Andrea, “Techniques for Digital Receivers” Plenum Press, New York, USA, 1997. (Chapter 7 + 8, pp. 353–476)

[8] Meyr, Moeneclaey, Fechtel, “Communication Receivers: Synchronization, Channel Estimation, and Signal Processing” Wiley Series in Telecommunications and Signal Processing Wiley Series), John Wiley & Sons, Inc., New York, USA, 1998 (pp. 79-147, 229-232)

[9] C. Rohde, N. Alagha, R. De Gaudenzi, H. Stadali, G. Mocker, "Super-Framing: A Powerful Physical Layer Frame Structure for Next Generation Satellite Broadband Systems Strong physical layer frame structure for the International Journal of Satellite Communications and Networking (IJSCN), Wiley Press, vol. 34, no. 3, pp. 413-438, November 2015, SAT -15-0037.R1.Available: http://dx.doi.org/10.1002/sat.1153

Claims (71)

An adjustable sample provider 604, configured to provide samples of the input signal using adjustable sample timing;
A feedback path 630 configured to provide a feedback signal to the tunable sample provider 604 based on a timing error 634-the feedback path 630 is the tunable sample provider ( 604) includes a loop filter 636 that is configured to provide sample timing information 638; And
Replacement sample timing information that replaces the sample timing information 638 provided by the feedback path 630 when the input signal does not achieve a predetermined requirement for feedback-based sample timing adaptation ( replacement sample provider (640) configured to provide replacement sample timing information (642),
The replacement value provider 640 derives from the timing error information 634 over a longer period of time compared to the time period considered by the loop filter 636 for providing the sample timing information 638 Receiver 110-116, configured to provide the replacement sample timing information 642, taking into account the quantity, or timing error information 634.
An adjustable sample provider 604 configured to provide samples of the input signal using adjustable sample timing;
A feedback path 630 configured to provide a feedback signal 638 to the adjustable sample provider 604 based on a timing error 634-the feedback path 630 is the adjustable A loop filter 636, configured to provide sample timing information 638 to the sample provider 604; And
Replacement sample timing information (replacement) that replaces the sample timing information 638 provided by the feedback path 630 when the input signal does not meet the predetermined requirements for feedback-based sample timing adaptation. a replacement value provider 640 configured to provide sample timing information 642,
The replacement value provider 640 temporarily samples the timing information 638 provided by the loop filter 636 and/or loop filter-internal timing information to obtain the replacement sample timing information. Receiver (110-116), configured to be temperally smoothen.
3. The method of claim 2, wherein the replacement value provider (640) is longer than the period of time for timing error information (634) considered by the loop filter (636) to provide current sample timing information (638). A receiver configured to average the quantity derived from the timing error information 634 over a period of and/or timing error information 634 and/or sample timing information 638 provided by the loop filter 636.
4. The method according to any one of the preceding claims, wherein the replacement value provider (640) averages over a longer period of time when compared to a loop filter (636) to provide the replacement sample timing information (642). Or configured to filter.
5. The average or equal weighted averaging method according to any one of claims 1 to 4, wherein the loop filter (640) is a low pass filter and gives less weight to past input values when compared to current input values. a receiver configured to perform (equally weighted averaging).
The method according to any one of the preceding claims, wherein the replacement value provider (640) is an amount derived from the timing error information (634), and/or timing error information (634) and/or the loop filter ( 636) configured to perform linear averaging by means of equal or different weights for the input values of sample timing information 638 provided by the receiver.
7. Receiver according to any of the preceding claims, wherein the replacement value provider (640) is configured to select samples of the sample timing information (638) to perform filtering or averaging on the selected samples. .
The method according to any one of claims 1 to 7, wherein the replacement value provider (640) is an amount derived from the timing error information (634) to perform filtering or averaging on the selected samples, Or configured to perform analysis of the signal to adaptively select samples of the timing error information 634,
The receiver is configured to increase the number of selected samples for signals with relatively high noise and/or reduce the distance between the selected samples when compared to signals with relatively low noise.
9. The method of any one of claims 1 to 8, wherein the replacement value provider (640) increases the average gain over an average length or filter length, A receiver configured to adaptively select samples to perform filtering or averaging on selected samples.
10. Receiver according to any one of the preceding claims, wherein the replacement value provider (640) is configured to use a down sampled version to perform filtering or averaging on the down sample version.
The amount of any one of claims 1 to 10, wherein the replacement value provider (640) is derived from the timing error information (634) to perform filtering or averaging on the downsample version. Or configured to use a down-sampled version of the timing error information 634,
The sampling rate of the down-sampled version is between 100 and 10000 or 500 and 2000 times slower than the amount derived from the timing error information 634 or the sampling rate of the timing error information 634. A receiver that is the first sampling rate between.
12. The timing according to any one of the preceding claims, wherein the replacement value provider (640) is derived from the timing error information (634) for the provision of the replacement timing information (638), or the timing. Configured to selectively consider samples of error information 634,
The current replacement timing information 642 is obtained based on samples of at least two different considered time periods of the input signal 602 while the input signal satisfies a predetermined condition.
13. The method according to any one of the preceding claims, wherein the replacement value provider (640) is based on a lookup table and/or configuration data according to a communication scenario or configuration. Thus, a receiver configured to select samples derived from the timing error information 634 or the timing error information 634.
14. The replacement sample timing according to any one of claims 1 to 13, wherein the replacement value provider (640) is based on an amount derived from the timing error information (634) or an analysis of the timing error information (634). A receiver configured to adaptively select an amount derived from the timing error information 634 for the derivation of information 642, or samples of the timing error information 634.
15. The receiver according to any one of the preceding claims, configured to increase the loop gain and/or the loop filter characteristic for an initial transitory interval.
16. The receiver of any of claims 1-15, configured to re-configure the loop gain/loop filter characteristics while operating based on modified reception conditions.
17. The loop filter (636) according to any one of claims 1 to 16, for signals having a relatively high SNR, relative to signals having a relatively low signal to noise ratio (SNR). ) And/or the loop filter characteristic of the loop filter 636 for the signal having a relatively low SNR in relation to a signal having a relatively high SNR and/or to increase the loop gain and/or A receiver, configured to reduce the loop gain.
The feedback mode and the replacement sample timing information (18) according to any one of the preceding claims, wherein the feedback signal from the feedback path (630) is provided to the adjustable sample provider (604). A receiver configured to switch between a replacement value provision mode 642 provided to the tunable sample provider 604.
19. The method of claim 18, wherein intermediate values are configured to switch to an intermediate mode provided to the adjustable sample provider (604), wherein the intermediate values are replaced with the values of the feedback signal. Obtained as values between sample timing information 642 −
The transition 644 is from the feedback mode to the intermediate mode and from the intermediate mode to the replacement value providing mode, and/or the switching 644 is from the replacement value providing mode to the intermediate mode and from the intermediate mode. A receiver, which is a transition to the feedback mode.
20. The receiver of claim 19, configured to provide intermediate replacement sample timing information (624) to smooth transition from the feedback mode to the replacement value providing mode or vice versa.
21. Receiver according to any of the preceding claims, configured to provide reconstruction information (646) and/or data (646) from the replacement value provider (640) to the loop filter (636).
A controller unit (650, 654) for recognizing a transmission to be received, which determines whether the power of a received signal or a quantity (656) from the power lies in a limited interval. Do that, and
Based on the determination, a controller unit (650, 654) configured to recognize the transmission to be received.
23. The controller unit (650, 654) of claim 22, configured to identify whether the received signal (602) includes a previously determined power level.
24. The method of any one of claims 22 and 23 for recognizing the length (712) of at least one limited time period while the received signal (602) comprises a power level (P0, P1, P2). , A controller unit (650, 654) configured to determine an amount derived from the received signal, or how long the power of the received signal (602) lies within the limited interval (702).
25. The method of claim 24, configured to check whether the recognized length of the limited time period while the received signal includes the power level satisfies a predetermined condition to support recognition of a transmission to be received, Controller units (650, 654).
26. Controller unit (650, 654) according to any one of claims 22 to 25, configured to recognize the received signal, or the amount of different power levels derived from the power.
27. The controller unit (650, 654) of claim 26, configured to track the duration at which the different power levels appear to derive power level scheduling information.
36. The method of claim 35, configured to check whether the current power level lies in a limited interval (702) and interval boundaries (704, 706) determined based on the previously derived power level scheduling information. , Controller unit (650, 654).
29. The components (604, 608, 612, 620) or processing (28) of the processing (600) or of the receiver (110-114) based on the derived power level scheduling information. 600) or a controller unit (650, 654), configured to selectively switch the receiver (110-114) to a reduced-power-consumption mode (699).
30. The time period of any one of claims 22 to 29 for re-configuring the receiver (600) for different time periods and/or for the transmission to be received. Configured to recognize the periods of time during which the different power levels appear and the amount derived from the power, or different power levels of the received signal 602, to rank the different time periods to recognize them, Controller units (650, 654).
31. The time period according to any one of claims 22 to 30, for selecting a time period having a relatively high power level in relation to a time period having a relatively low power level as the time period for the transmission to be received. , A controller unit (650, 654) configured to recognize different power levels of the received signal, or of the amount derived from the power.
32. The power level of any one of claims 22 to 31 to store time information depicting characteristics of time portions of different levels of the received signal and the power level of the received signal, or to store time information. Configured to store information about the fields,
At the next moments, a controller unit (650, 654) configured to recognize time periods associated with the transmission to be received, at least based on the stored time information.
33. The special activation mode “exploit other illumination” according to any one of claims 22 to 32, based on the credentials of the other illumination(s) and the detection of different illumination power levels. Further comprising, the controller unit (650, 654).
34. Controller unit (650, 654) according to any of claims 22 to 33, configured to determine the start and/or the end of a period of transmission to be received based on the power level.
35. Decoding and/or detecting at least one piece of information encoded in the received signal according to any one of claims 22 to 34 to determine the start and/or the end of a period of transmission to be received. Controller unit 650, 654.
36. The method of any one of claims 22 to 35, wherein detecting a slope of the power above or below a predetermined threshold, using time information obtained with previous power level determinations, received signal Decoding specific information encoded in, and/or detecting quality information or deducing it from other modules, using data signaled from a transmitter and/or commands A controller unit (650, 654) configured to recognize the start and/or the end of the period of the transmission to be received by a redundant or supporting technique comprising at least one of.
37. The method of any one of claims 22 to 36, wherein the at least one power level is based on the determination that at least two consecutive power samples lie within limited intervals associated with the specific power level. Controller units 650, 654, configured to be recognized and/or dynamically defined.
38. The method according to any one of claims 22 to 37, wherein, as a first condition, a positive sample derived from the power, or a current sample of the power of the received signal, is derived from the power, or Determine whether they lie within an interval determined by the first preceding sample of power, and
As a second condition, an interval determined by the positive, derived from the power, or the current sample of the power of the received signal is also the positive, derived from the power, or a second preceding sample of the power of the received signal Configured to determine if it lies within,
A controller unit (650, 654) configured to recognize a continuity of power levels when both the first condition and the second condition are satisfied.
The positive number derived from the power that does not satisfy the first condition and/or the second condition without recognizing the end of the power level, or a predetermined number of the power of the received signal. Configured to tolerate successive samples of
Configured to recognize the end of the power level if the positive, or successive samples of the power of the received signal, derived from a greater number of power than a predetermined number do not satisfy the first condition or the second condition , Controller unit (650, 654).
40. The power of any of claims 22 to 39, wherein the positive sample derived from the power, or the current sample of the power of the received signal, is derived from the power, or the received signal. It is also configured to determine whether it lies outside the tolerance interval 742 greater than the interval 744 determined by the immediately preceding sample of
A controller unit (650, 654) configured to recognize the end of the power level when the current sample of the positive, or the power of the received signal derived from the power is first placed outside the allowable interval (744).
41. The method of any one of claims 22-40, further configured to operate along at least first and second modes of operation, in at least one of the first and second modes of operation
A technique for determining whether the amount derived from the power or the power of the received signal lies within a limited interval,
Technology to determine if power is determined at the expected time period,
A technology for decoding or detecting specific information encoded in the signal to be received,
Technology to check quality information,
Technology to check the satisfaction of the criteria according to the information signaled from the transmitter,
Configured to perform at least one of techniques for detecting whether the slope in the power is above or below a predetermined threshold,
The controller units 650, 654 are configured to use at least one different technique in the first mode of operation in relation to the second mode of operation, the controller units 650, 654.
The method according to any one of claims 22 to 41,
A first mode for determining whether the amount derived from the power or the power of the received signal lies within a limited interval, without considering the information encoded in the signal; And
Determine based on whether the amount derived from the power, or the power of the received signal lies within a limited interval, and whether the encoded information in the received signal conforms to the recognition of the transmission to be received based on the power. 2nd mode to verify the above accuracy of
A controller unit (650, 654), configured to operate along at least two modes of operation.
43. The method of any one of claims 22-42, configured to derive or obtain an amount derived from the power from an automatic gain control (AGC), and/or a matched filter (608). , Controller unit (650, 654).
44. A controller unit (650, 654) according to any one of claims 22 to 43, wherein the amount associated with the power is an infinite impulse response (IRR) filtered version of the power information.
The method according to any one of claims 22 to 44,
Power for determining at least one power level used later to recognize a transmission to be received;
Time information;
Configured to perform an initialization process to obtain parameters related to at least one of the quality information or a combination thereof,
The controller units 650 and 654 receive the signaled information to perform the initialization, or the amount derived from the power over the period of the received signal to perform the initialization, Or a controller unit (650, 654), configured to analyze the temporal evolution of the power.
The upper interval boundary value and the lower interval boundary value for the power according to any one of claims 22 to 45, wherein the power is based on historical values of the power. The controller unit (650, 654), configured to adaptively modify.
47. The controller unit (650, 654) of any one of claims 22-46, configured to control the receiver of at least one of the claims 1-21.
The method according to any one of claims 22 to 47,
A first state in which the feedback path 630 provides the feedback path 638 to the adjustable sample provider 604; And
A second state where the replacement value provider 640 provides the replacement sample timing information 642 to the adjustable sample provider 604
A controller unit (650, 654), configured to control the receiver of at least one of the preceding claims to select from.
49. The method of any one of claims 22 to 48, to control the receiver of at least one of the preceding claims (1 to 21) to determine the predetermined requirement to be satisfied by the input signal (602). Constructed, controller units (650, 654).
50. The adjustable sample provider according to any one of claims 22 to 49, wherein the feedback signal (638) is sent to the feedback path (630) when the controller unit (650, 654) recognizes that the transmission will be received. Providing to 604; And/or
The replacement sample timing information 642 is adjusted by the adjustable sample provider 604 when the replacement value provider 640 recognizes that the controller unit 650, 654 is not a transmission to be received or there is no transmission. )
A controller unit (650, 654), configured to control the receiver of at least one of claims 1 to 21 to select.
The receiver according to any one of claims 1 to 21 and 63 to 70, further comprising the controller unit (650, 654) of any one of claims 22 to 50.
A transmitter (102) and a receiver (104-108, 600), said receiver (104) according to any one of claims 1 to 22 and 51 and any one of claims 63 to 70 (104) -108, 600), wherein the transmitter is configured to transmit a signal to the receiver.
53. The system (100) of claim 52, wherein the transmitter is a satellite.
53. The method of claim 52 or 53, wherein the transmitter is configured to perform transmission according to a beam-switching time plan (BSTP) transmission and/or according to a scheduling transmission,
The BSTP and/or the scheduling are defined such that for at least one first interval the signal is intended to be transmitted to the receiver, and for at least one second interval the signal is not intended to be transmitted to the receiver, System 100.
55. The method of claim 54, comprising a plurality of receivers, the transmitter to temporarily target a specific beam according to BSTP and/or scheduling such that the signal power is temporarily improved in the direction of the intended receiver. Constructed, system 100.
56. The receiver of any one of claims 52 to 55, wherein the receiver is configured to use the feedback signal (638) in the determination that the transmitter is directed to the receiver and in the determination that the transmitter is not intended for the receiver. And/or to use the replacement sample timing information 642 in the non-determination of transmission from the transmitter.
57. The transmitter of any of claims 52-56, wherein the transmitter has at least a continuous signal condition in which the beam is continuously directed to the receiver, and a bursty signal condition in which different beams are directed at different receivers. System 100, configured to operate in accordance with).
Processing samples 604 of the input signal using adjustable sample timing;
Matching the sample timing based on a feedback signal 638 based on a timing error 634, the feedback signal 638 being obtained using a loop filter 636 providing sample timing information 638; And
Providing replacement sample timing information (642) to replace the sample timing information provided with the feedback signal (638) when the input signal does not satisfy a predetermined requirement for feedback based sample timing adaptation; ,
The replacement sample timing information 642 is an amount derived from the timing error information 634 over a longer period of time compared to the time period considered by the loop filter 636 to provide the sample timing information. Or, taking into account timing error information 634, a method for receiving an input signal.
Processing samples of the input signal using adjustable sample timing;
Matching the sample timing based on a feedback signal based on a timing error, wherein the feedback signal 638 is obtained using a loop filter 636 providing sample timing information 638; And
Providing replacement sample timing information 642 to replace the sample timing information provided with the feedback signal when the input signal does not satisfy a predetermined requirement for feedback based sample timing adaptation,
The replacement sample timing information 642 is obtained by temporarily smoothing the sample timing information provided by the loop filter 636 to obtain the replacement sample timing information 642.
Determining an amount derived from the power 656, or whether the power of the received signal lies within a limited interval, and
And recognizing a transmission to be received based on the determination.
The method of claim 60; And
The method of claim 60 comprising the method of claim 58 or 59, the provision of the replacement sample timing information 642 of the method of claim 68 or 69 and the provision of the feedback signal 638. Controlled by, method.
A computer program, when executed by a processor, performing at least one of the methods of claims 58-61 and 71.
The method according to any one of claims 1 to 22,
The first frame candidate 1000 at the expected position and
Find at least one second frame candidate (1002, 1004) shifted from the first frame candidate for a predetermined offset,
Evaluate characteristics of the at least one second frame candidate and the first frame candidate,
And a data processor (820) configured to identify the correct frame based on the evaluation.
64. The receiver of claim 63, configured to perform cross-correlation processes between known sequences of each frame candidate and symbols to identify the correct frame based on the cross-correlation processes.
The method of claim 63 or 64,
To identify the correct frame based on the cross-correlation processes,
Demodulate and/or decode the frame headers of the first and second frame candidates,
Re-modulate and/or re-encode the sequence of symbols, and
A receiver configured to perform the cross-correlation processes between each frame candidate frame header and the re-modulated and/or re-encoded version of the frame candidate frame header.
The method according to any one of claims 63 to 65,
Start/end and/or frame symbols 804 of frame signaling 806 to compensate for the detected temporal offset between the frame signaling 806 and the frame symbols 804 A receiver configured to perform a correction procedure for a receiver.
67. The receiver of any one of claims 63-66, configured to perform an evaluation operation on the results of the correlation processes to verify the correct frame.
68. The method of claim 67, wherein the frame is the only frame candidate associated with a correlation value greater than the first predetermined threshold, and a first threshold (902) and each frame candidate to verify the correct frame. A receiver, configured to compare each of the cross-correlation results related to.
69. The method of claim 67 or 68, wherein at least a predetermined number of frame candidates are associated with each frame to suppress verifying the correct frame when associated with the smaller predetermined threshold and cross-correlation values within the larger predetermined threshold. Configured to compare each of the cross-correlation results associated with a candidate to a larger threshold and a smaller predetermined threshold,
Error in the attestation that the predetermined number of frame candidates is associated with a cross correlation value greater than the predetermined threshold and at least a predetermined number of frame candidates is associated with a cross correlation value smaller than the smaller predetermined threshold. Receiver configured to notify.
69. The method of any one of claims 67-69, wherein at least a predetermined number of frame candidates are associated with cross correlation values greater than the predetermined threshold and at least a predetermined number of frame candidates is greater than the smaller predetermined threshold. When associated with smaller cross-correlation values, configured to compare each of the cross-correlation results associated with each frame candidate to a larger predetermined threshold and a smaller predetermined threshold to suppress verifying the correct frame, and
Error in the attestation that the predetermined number of frame candidates is associated with cross correlation values greater than the predetermined threshold and at least a predetermined number of frame candidates is associated with cross correlation values smaller than the smaller predetermined threshold. Receiver configured to notify.
62. The method of any one of claims 58-61, further comprising: a first frame candidate (1000) at an expected location; And
Finding at least one second frame candidate (1002, 1004) shifted from the first frame candidate for a predetermined offset;
Evaluating characteristics of the at least one second frame candidate and the first frame candidate;
Identifying the correct frame based on the evaluation
The method further comprising.

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